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There is only one constant in the NFL, and that's change. After three consecutive offseasons that saw 25% of the league’s head coaches replaced, we ‘only’ had seven changes (22%). There was more balance this year as four of the hires were offensive-minded coaches while three were from the defensive side of the ball (last year 7-of-8 were offensive-minded). Three coaches (Jim Caldwell, Lovie Smith and Ken Whisenhunt) have former NFL head coaching experience, while the others (Jay Gruden, Bill O’Brien, Mike Pettine and Mike Zimmer) have been NFL coordinators.

Speaking of NFL coordinators, 23 of the league’s 64 offensive and defensive coordinators were replaced. Including the head coaching changes, 31% of the NFL’s most important coaching positions are different from a season ago. Thinking about this another way, only half of the league returns the same trio at head coach, offensive and defensive coordinator.

The NFL is both a cyclical league and one prone to copy cats. When something works for a team, you can be sure other teams will look to duplicate that success; and it doesn't always work. Not every iteration of the West Coast offense enjoyed the success of the Bill Walsh 49ers. Not every version of Dick LeBeau's zone-blitz stopped opposing quarterbacks. With that in mind, today's trends including the zone-read, spread attacks and no huddle approaches will have a mix of successes and failures. That's the very nature of the league as success only comes with the confluence of great coaching, great players and health.

Below we detail each team’s major coaching changes and the schematic implications of those hires. As always, we will continue to update our views throughout the year as more information is made available in training camp and the preseason.

Baltimore Ravens

• Head Coach: John Harbaugh
• Offensive Coordinator: Gary Kubiak (replaces Jim Caldwell)
• Defensive Coordinator: Dean Pees

What to expect on offense: Jim Caldwell took over mid-2012 and led the Ravens offense to a turnaround good enough for Baltimore to capture their second Super Bowl. Unfortunately Caldwell’s impact was short lived, and the Ravens regressed miserably in 2013 – finishing 25th in points scored and 29th in offensive yards. The collapse was seen in all facets of the game (30th in net yards per pass attempt, 32nd in rushing yard per carry), which makes losing Caldwell (who took the Lions head coaching job) more palatable than one might have otherwise expected.

Gary Kubiak returns to the role of offensive coordinator for the first time since 2005, when he was Mike Shanahan’s right hand man in Denver. Kubiak cut his teeth in the traditional West Coast offense, but have combined those principles with a concept-based approach most notably associated with the Erhardt-Perkins coaching tree. Concept-based play-calling essentially allows teams to run the same play from any formation or personnel grouping. It effectively separates the play (routes, blocking assignments, spacing) from the personnel grouping. Believers argue it gives the quarterback more freedom and speeds up the game.

Kubiak’s offenses were wildly inconsistent in Houston, which makes handicapping his impact on the Ravens difficult. In eight seasons in Houston, Kubiak’s teams ranged from 1st to 27th in passing yards, 3rd to 29th in passing TDs, 2nd to 30th in rushing yards, and 1st to 28th in rushing TDs. Immediate success will come down to whether the Ravens offensive personnel fits into the system. The offensive line has to be mobile in Kubiak’s zone-blocking system, and QB Joe Flacco will be asked to make plays out of the pocket more frequently.

Buffalo Bills

• Head Coach: Doug Marrone
• Offensive Coordinator: Nathaniel Hackett
• Defensive Coordinator: Mike Schwartz (replaces Mike Pettine)

What to expect on defense: Mike Pettine’s tenure in Buffalo lasted one season after landing the Cleveland Browns head coaching job. HC Doug Marrone tapped Jim Schwartz (fresh off his stint as the Lions head coach) to handle the defensive play-calling. Schwartz is well-respected throughout the league as a dedicated, aggressive coach. In that way he and Pettine are similar; but the differences are vast. Pettine used multiple formations and his goal was to foster confusion from opposing offenses. Pettine’s defense couldn’t be defined by a particular look. Schwartz has a different philosophy. He has no interest in tricking his opponents – his teams line up primarily in a 4-3 front and attack. Schwartz often utilizes the “Wide 9”, which calls for both defensive ends to line up far outside of the tackles, thus forcing pressure from the inside and driving all the running lanes inside to be cleaned up by the linebackers.

Cincinnati Bengals

• Head Coach: Marvin Lewis
• Offensive Coordinator: Hue Jackson (replaces Jay Gruden)
• Defensive Coordinator: Paul Guenther (replaces Mike Zimmer)

What to expect on offense: Hue Jackson steps into the role of offensive coordinator after a season coaching the Bengals running backs. Immediately upon being named OC, Jackson promised a stronger commitment to the running game. While that sounds great in theory, Bengals fans should take Jackson’s promises with a grain of salt. After all, former OC Jay Gruden was hardly pass happy. The Bengals ranked 8th in rushing attempts last season (12th in passing attempts). Furthermore, Jackson has been an offensive coordinator for three other NFL teams (Washington, Atlanta and Oakland) with uneven results. Jackson lasted just one season as play-caller in both Washington and Atlanta, and managed two seasons as the play-caller in Oakland. His offenses were league average or worse three of four seasons. In other words, there’s not a lot of evidence to suggest Hue Jackson will be an upgrade over Jay Gruden. We could be proven wrong, but fantasy owners shouldn’t bet on it.

What to expect on defense: Sometimes promoting from within can be uninspired (e.g., Hue Jackson), but other times it’s the smart move – such as the Bengals decision to promote Paul Guenther from his role of LB coach in place of Mike Zimmer. Guenther has been under Marvin Lewis and Mike Zimmer’s coaching tree for nearly a decade, and was on several teams’ short list for open defensive coordinator roles. Guenther will maintain his predecessor’s terminology and concepts, but promises more varied defensive fronts in order to put the team’s best players in optimal matchups.

Cleveland Browns

• Head Coach: Mike Pettine (replaces Rob Chudzinski)
• Offensive Coordinator: Kyle Shanahan (replaces Norv Turner)
• Defensive Coordinator: Jim O’Niel (replaces Ray Horton)

What to expect on offense: Kyle Shanahan is most commonly perceived as a West Coast offense disciple thanks to his time working under his father, Mike Shanahan, and Gary Kubiak (a long-time Shanahan assistant) in Houston. Yet, Shanahan’s play-calling tendencies argue for a broader approach to the game. Much like Kubiak, Shanahan embraces core concepts of the West Coast offense but has tailored his game plans to feature concepts. The good news for Browns fans is that Shanahan has had success as a play-caller, finishing in the top 10 offensively in four of six seasons.

The Browns offense is going to look much different from last season, where Rob Chudzinski and Norv Turner tried to implement an aggressive downfield passing attack. You can be sure Shanahan will try to create balance between the run and pass, particularly if the Browns defense keeps the team in games. Shanahan has shown a willingness and ability to adapt to his personnel, which will be essential considering the Browns have uncertainty at quarterback and receiver.

What to expect on defense: Pettine and DC Jim O’Neil will work closely together; O’Neil was the linebackers coach in Buffalo under Pettine. Pettine had previously been Rex Ryan’s right hand man in New York; which led some to question whether Pettine was an impact defensive mind or merely the beneficiary of Rex Ryan’s aptitude. Last year in Buffalo Pettine answered the critics by turning the league’s 26th ranked defense (2012) into a top 10 unit a year ago. The Bills excelled in creating turnovers last year and attacked from varied fronts, a key weapon in the era of read option offense.

O’Niel and Pettine plan on bringing their penchant for multiple schemes to a Browns defense that has added a ton of talent this offseason. The Browns will feature multiple fronts (i.e., 4-3, 3-4, 5-2) and the defensive backs will be expected to play both man and zone interchangeably. The challenge, much as it was last year in Buffalo, will be getting a new roster up to speed on Pettine’s complex approach.

Dallas Cowboys

• Head Coach: Jason Garrett
• Offensive Coordinator: Scott Linehan (joins Bill Callahan)
• Defensive Coordinator: Rod Marinelli (replaces Monte Kiffin)

What to expect on offense: The Cowboys are never without drama, and the offensive meeting rooms could yield fireworks. After all, Jason Garrett and Bill Callahan remain in place, but Scott Linehan was hired and effectively handed the play-calling duties. In terms of Xs and Os, the addition of Linehan should excite fantasy owners. Let’s remember he has brought the best out of Marc Bulger (in St. Louis), Daunte Culpepper (in Minnesota) and Matthew Stafford (in Detroit).

Linehan is from the same coaching tree as Garrett (in fact, Linehan hired Garrett as his QB coach in Miami) and they’ll continue to use many of the classic Air Coryell concepts; in particular play-action to set up vertical passing. The terminology will be similar enough for Tony Romo and the skill players to grasp quickly; an exciting prospect considering how prolific Linehan’s offenses have been when he’s had supporting talent.

What to expect on defense: When the Cowboys hired Monte Kiffin last year, it was widely expected Rod Marinelli would take over the coordinator role in a season or two. After all, Kiffin was 73 years old and Marinelli was considered his top assistant and fellow acolyte of the Tampa Cover-2 defense. Unfortunately, Cowboys fans need to ask themselves whether Marinelli’s ascension (Kiffin retired) is going to matter. The defense got worse, not better in 2013 – finishing 26th and 32nd in points and yards allowed, respectively. On top of that, Marinelli must deal with the loss of LB Sean Lee (injury) and DeMarcus Ware (cap casualty). This unit may simply not have the horses to match Marinelli’s expertise.

Detroit Lions

• Head Coach: Jim Caldwell (replaces Jim Schwartz)
• Offensive Coordinator: Joe Lombardi (replaces Scott Linehan)
• Defensive Coordinator: Teryl Austin (replaces Gunther Cunningham)

What to expect on offense: The Lions jettisoned a defensive minded head coach in favor of the offensive minded Jim Caldwell. Caldwell has prior head coaching experience in Indianapolis, but it’s hard to get a read on Caldwell’s offensive capabilities based on those three seasons. In his first two years Peyton Manning was his usual self and the offenses were elite. Yet, when Manning got hurt in 2011 the Colts fell apart (30th in yards and 28th in points) and Caldwell seemed overmatched. He seemed to re-establish himself two seasons ago in Baltimore when an in-season promotion helped the Ravens offense find new life and make a run all the way to the Super Bowl title. Confusingly, the gains the Ravens showed in 2012 were entirely forgotten in 2013 as Caldwell’s unit fell to 29th in yards and 25th in points. So will the real Jim Caldwell please stand up?

Perhaps the key to understanding the fate of the Lions offense lies instead with the hiring of offensive coordinator Joe Lombardi. Caldwell plans to let Lombardi call the plays, even though it will be Lombardi’s first season as an NFL coordinator. Lombardi has been an assistant in New Orleans since 2007 and promises the new Lions offense will closely resemble the Saints playbook. That means Lombardi will be installing a diverse, aggressive attack that looks to exploit mismatches perceived in studying the opposing defense. Lombardi’s mentor – Sean Peyton – gathered elements from the West Coast, Coryell and Erhardt-Perkins systems and made them his own. Lombardi plans on doing the same, and believes Matthew Stafford is talented enough to execute his system at a high level.

What to expect on defense: Teryl Austin is installing an entirely new defense, one that will barely resemble the system Jim Schwartz and Gunther Cunningham preferred. Austin spent the last three seasons coaching defensive backs in Baltimore. He promises a defense that favors multiple looks and brings pressure from different positions. Austin prefers a 4-man rush generally, and will mix and match man and zone coverage in the secondary. Unlike his predecessors, Austin prefers his defensive backs to press The critical component to Austin’s defense is on-field communication. He’s going to need players like Stephen Tulloch and Glover Quin to quickly become defensive quarterbacks, making sure the defense is as good at adjusting at the line of scrimmage as the opposing offense.

Houston Texans

• Head Coach: Bill O’Brien (replaces Gary Kubiak)
• Offensive Coordinator: Bill O’Brien (replaces Rick Dennison)
• Defensive Coordinator: Romeo Crennel (replaces Wade Phillips)

What to expect on offense: Bill O’Brien made a name for himself under Bill Belichick and then took on the daunting challenge of replacing Joe Paterno at Penn State. The chance to take over the Houston Texans lured him back to the NFL. Presumably O’Brien was intrigued by the opportunity to take over a team that finished with the worst record in the league, yet has some compelling pieces on both sides of the ball. Many expected O’Brien to draft a quarterback with the first overall pick, instead the team added defensive end Jadaveon Clowney. The 2014 season appears to be a year when journeyman Ryan Fitzpatrick will man the huddle, and the Texans will continue to search for their franchise passer in next year’s draft or in free agency.

O’Brien will call his own plays (he’s opted against hiring a coordinator) and will bring a varied offense similar to what we’ve seen from the Patriots. O’Brien believes in creating mismatches based on perceived weaknesses of the opposing defense. Expect the tight end position to be prominently featured, both in ‘move’ roles (as receivers) and as in-line blockers. If the game script allows, O’Brien also wants to emphasize the run but will need his offensive line to come together, and hope that Arian Foster can return to form.

What to expect on defense: Romeo Crennel is a known commodity, and has overseen NFL defenses for 12 straight seasons. Crennel strongly favors a traditional two-gap, 3-4 defensive front. For that scheme to be successful the three defensive linemenhave to hold their blocks and then react – that’s not necessarily an ideal fit for J.J. Watt. Crennel has also asked his outside linebackers to cover intermediate passing routes, which is a questionable use of Clowney. Suffice to say, there are lots of questions left unanswered in spite of Crennel’s reputation. One final note of caution, Crennel hasn’t field a top 10 defense since he left the Patriots in 2004.

Miami Dolphins

• Head Coach: Joe Philbin
• Offensive Coordinator: Bill Lazor (replaces Mike Sherman)
• Defensive Coordinator: Kevin Coyle

What to expect on offense: Dan Reeves, Mike Holmgren, Joe Gibbs and Chip Kelly. Those are the NFL head coaches Bill Lazor has apprenticed under. That tells you two things: 1) Lazor has learned from some of the best offensive minds in league history, and 2) Lazor has been exposed to a variety of offensive systems. How that will translate into play-calling for the 2014 Dolphins remains a mystery. This will be Lazor’s first foray at calling plays at this level, and all we know for sure if he promises to build a balanced offense that will dictate tempo. Presumably Lazor will incorporate a fair amount of the West Coast offense since that’s what QB Ryan Tannehill has been familiar with in college and the pros. Yet Lazor will look to the ground attack to set the tone, but only if he and his offensive assistants to assemble a cohesive offense line.

Minnesota Vikings

• Head Coach: Mike Zimmer (replaces Leslie Frazier)
• Offensive Coordinator: Norv Turner (replaces Bill Musgrave)
• Defensive Coordinator: George Edwards (replaces Alan Williams)

What to expect on offense: This year Norv Turner will call plays for his eighth NFL franchise; an astounding achievement and a testament to the veteran coach’s reputation. Turner has been calling plays in the NFL since 1991 and is the most experienced remaining disciple of Don Coryell’s offensive school. Turner’s system uses a traditional route tree approach to the passing game, and a power run blocking scheme. There’s little question Adrian Peterson will be the cornerstone offensively, but that would’ve been the case no matter who ran the offense. Turner’s biggest challenge will be in crafting a passing attack either with rookie Teddy Bridgewater or veteran Matt Cassel. Some have questioned whether Turner has lost his edge as an in-game coach, but that’s being myopic. The 2013 Browns were bereft of talent and let’s not forget Turner’s Chargers ranked in the top 5 offensively for five consecutive seasons (2007-2011). Not coincidentally those teams had an all-world running back, just like the Vikings.

What to expect on defense: Leslie Frazier is a strong defensive mind but his message stopped resonating in the Vikings locker room as the defense fell to 31st last year. Mike Zimmer is among the league’s most respected defensive coaches, having built top 10 defenses in three stops (Atlanta, Dallas and most recently Cincinnati). Zimmer has enjoyed success with both 3-4 and 4-3 base fronts, but most expect the Vikings to use the 4-3 primarily. Zimmer loves to blitz and will call a more aggressive game than Frazier. He brings pressure the secondary, and asks his defensive backs to play man coverage frequently as a result. Zimmer’s hiring is about more than scheme, it’s about his ability to adjust in-game – something that many defensive coaches try but few excel.

New York Giants

• Head Coach: Tom Coughlin
• Offensive Coordinator: Ben McAdoo (replaces Kevin Gilbride)
• Defensive Coordinator: Perry Fewell

What to expect on offense: Option routes. Kevin Gilbride’s preference for option routes (where receivers make the decision to run a particular route based on what the defense does) was blamed for the Giants disappointing 2013 (28th in both yards and points scored). The problem with that line of thinking is that Kevin Gilbride’s same offense ranked in the top 10 of points scored in the five previous seasons. Option routes didn’t seem to be problematic in those seasons. A more reasonable criticism of Gilbride was his rigidity of approach. Gilbride was unwilling or unable to adjust his game plan to suit the needs/deficiencies of his personnel.

Regardless, last year’s struggles led to the hiring of Ben McAdoo, who comes over from Mike McCarthy’s staff in Green Bay. McAdoo will implement a West Coast offense, a system QB Eli Manning has never played but should help Manning mitigate his interception rate. If McAdoo’s experience in Green Bay is any indication, the Giants will run a faster pace, utilize the no huddle at times, and will make liberal use of the shotgun. McAdoo has the pedigree for success, but ultimately his first year will be defined by whether or not the Giants offensive line can return to form.

St. Louis Rams

• Head Coach: Jeff Fisher
• Offensive Coordinator: Brian Schottenheimer
• Defensive Coordinator: Gregg Williams (replaces Tim Walton)

What to expect on defense: Tim Walton was one and done in St. Louis, and HC Jeff Fisher tapped his long-time friend and associate Gregg Williams as the new defensive coordinator. Williams is infamous for his role in the ‘Bountygate’ scandal that led to his indefinite suspension, which precluded him from joining Fisher’s staff in 2012. Reinstated last year, Williams worked as a defensive assistant in Tennessee but will now be back with Fisher in the role he was intended for two seasons ago.

Williams uses 4-3 fronts and is among the most aggressive blitzers in the league. He loves bringing pressure from everywhere, and will frequently bring two or three extra pass rushers. That requires his defensive backs to lock down on the outside receivers. Another hallmark of Williams’ defense is complexity. The size of his playbook is legendary, and generally considered a better fit for a veteran laden squad.

San Diego Chargers

Head Coach: Mike McCoy
Offensive Coordinator: Frank Reich (replaces Ken Whisenhunt)
Defensive Coordinator: John Pagano

What to expect on offense: The old expression ‘if it ain’t broke don’t fix it’ applies in San Diego, where the Chargers made the logical move and promoted QB coach Frank Reich to replace Ken Whisenhunt(who accepted the Titans head coaching job). Reich will call the plays, but head coach Mike McCoy has promised to be more intimately involved in the weekly game-planning this year to help offset the loss of Whisenhunt’s experience. Schematically nothing will change, and that’s a great thing considering the Chargers finished 5th in points scored last season.

Tampa Bay Buccaneers

• Head Coach: Lovie Smith (replaces Greg Schiano)
• Offensive Coordinator: Jeff Tedford (replaces Mike Sullivan)
• Defensive Coordinator: Leslie Frazier (replaces Bill Sheridan)

What to expect on offense: When your offense is best characterized as complex, it’s unclear whether success is likely. In Jeff Tedford’s defense, his collegiate quarterbacks frequently found their way into the NFL first round, most notably Aaron Rodgers. Tedford expects an enormous amount from his starting quarterback, which begs the question of whether journeyman Josh McCown is the player who outplayed Jay Cutler in Chicago last year, or the unimpressive passer who threw just 37 touchdowns against 44 interceptions for five teams over ten years.

Stylistically Tedford prefers a downfield spread attack, and will use the shotgun frequently. His teams haven’t just been about smart quarterbacking, he’s found a way to get productive ground attacks out of smaller running backs like J.J. Arrington, Jahvid Best and Shane Vereen. Based on early commentary, Tedford appears to favor a committee approach which means Doug Martin is a risky pick to return to his elite 2012 form.

What to expect on defense: Lovie Smith and Leslie Frazier have both promised flexibility as they rebuild the Buccaneers defense, but their coaching histories suggest otherwise. Both men are highly accomplished defensive minds, and both have coached the Tampa Cover-2 almost exclusively. Expect a conventional 4-3 front and a defense that bends but doesn’t break. Both men prefer to get pass rush from the front four and let the back seven keep everything in front of them. That works but only if the personnel can shut opposing teams down in the red zone.

Tennessee Titans

• Head Coach: Ken Whisenhunt (replaces Mike Munchak)
• Offensive Coordinator: Jason Michael (replaces Dowell Loggains)
• Defensive Coordinator: Ray Horton (replaces Jerry Gray)

What to expect on offense: The Dowell Loggains era was over before it started, as the Titans lacked an identity and weren’t particularly effective in any facet. Ken Whisenhunt, the new head coach, will assuredly change that based on his successes in Pittsburgh, Arizona and Tennessee. Whisenhunt is from the Don Coryell school and wants a strong armed passer who can stand in the pocket and deliver balls downfield. His quarterback needs to make quick decisions, and Whisenhunt loves getting the RBs involved as outlet options in the passing game. Given OC Jason Michael’s pedigree (TE coach in San Diego, Oakland and San Francisco), you can be sure the Titans will emphasize Delanie Walker. The major question is whether Jake Locker is the quarterback Whisenhunt needs to succeed.

What to expect on defense: Ray Horton may be perceived as a 3-4 coach, but he has made it clear the Titans will use multiple looks (4-3, 3-4, 5-2, etc…) and will rotate their formations and personnel frequently. Horton likes to attack, but wants his defensive lineman to hold the line above all else. Horton balances man and zone coverage in the secondary and asks his defense to be able and willing to shift in pre-snap reads.

Washington Redskins

• Head Coach: Jay Gruden (replaces Mike Shanahan)
• Offensive Coordinator: Sean McVay (replaces Kyle Shanahan)
• Defensive Coordinator: Jim Haslett

What to expect on offense: Jay Gruden’s offenses in Cincinnati showed steady improvement, and the success he garnered from Andy Dalton hints at potential greatness from Robert Griffin III. On the surface, both Jay Gruden and Mike Shanahan are disciples of the West Coast offense. Yet, studying their game film you would be hard pressed to find many similarities. The great news for the Redskins players is that the base terminology doesn’t change; the learning curve shouldn’t be steep.

Gruden differs from Shanahan most notably in his approach toward the passing game. Both prefer high percentage passes and make liberal use of crossing routes. But Gruden has shown a willingness to take shots downfield more frequently. There’s no greater difference between the two than the approach to the running back position. Gruden uses a traditional man blocking scheme versus Shanahan’s zone blocking pedigree. Gruden also throws to his primary back quite a bit whereas Shanahan backs were rarely more than a last ditch safety outlet. Another change will be the frequency with which the Redskins use multiple-WR sets. Cincinnati used 3- and 4-WR sets far more often than Shanahan.