Photo: Imagn Images

NFL fans have spent decades arguing over whether a particular player is injury prone. Some view the NFL as a violent league where everyone is at risk of injury on every play: the players who actually suffer an injury are often simply victims of bad luck. Others believe that certain running backs are simply more injury prone than others.

Fantasy football is a complex game. But sometimes, I just want to see how a player performed when he actually played. The more specific you can get, the better, and I like gauge a player's fantasy potential before worrying about injuries or when he had a reduced role.

I looked at all running backs who scored at least 60 fantasy points in standard scoring leagues in 2012 (separate analysis follows at the end of this article for PPR leagues). I then noted how many quarters each of those running backs played in 2012. I included overtime quarters, so it's possible for a running back to play in more than 64 quarters, and two did so last season. If the running back had at least one rush attempt or one target in a quarter, he gets credit for playing in that quarter. But if a player was injured early in the first quarter, his production in that game will in essence be divided by just one-fourth of a game instead of a full game. By using a more granular approach to per-game numbers, we can really see which running backs played well in 2012 -- at least, whenever they were on the field. The table below shows each running back's fantasy points in 2012, number of games played, number of quarters involved, fantasy points per game, fantasy points per four quarters, and the running backs' ranks among these 53 RBs in FP, FP/G and Fantasy Points per Four Quarters (FP/4Q).

• Incredibly, the top seven running backs in fantasy points were also the top seven in fantasy points per game and fantasy points per quarter. That's pretty rare, which indicates that last year was a pretty healthy year for top backs.
• Andrew Brown ranked 9th in fantasy points per quarter, while Ahmad Bradshaw was 14th in that metric. This lets us know that the Giants running back -- whoever it was -- was very valuable last year. That's a good sign if you're expecting good things from David Wilson, although he will still have to compete with Brown for touches.
• Maurice Jones-Drew was 52nd in fantasy points, but 18th in fantasy points per quarter last year. He doesn't need to bounce back to be an RB2: he just needs to stay healthy.
• I'm not sure what to make of the fact that Knowshon Moreno and Willis McGahee were both in the top ten in fantasy points per quarter. But I do think drafting Montee Ball and Ronnie Hillman is a viable strategy in most leagues: the odds are good that one of them will be very productive most weeks. Denver usually plays with the lead, which should mean good things for either Ball or Hillman (or both).
• Chris Johnson ranked 12th in fantasy points, but just 21st in fantasy points per quarter.  Much of his value was tied in him staying healthy and getting a large number of carries. His ADP (RB13) includes some of that risk, but I would still avoid him at that price.
• Steven Jackson and Michael Turner finished 17th and 18th in fantasy points last year, but just 29th and 27th in fantasy points per quarter. Some are high on Jackson's potential in the Falcons offense (ADP of RB12), but perhaps this throws some cold water on those projections. Atlanta was a very pass-happy team last year despite their good record, and I don't expect that to change this year.

What if we do the same analysis for PPR leagues, using 75 FP as our minimum?

• LeSean McCoy was a top-six running back on both a per-game and per-quarter average last year in PPR leagues. He is healthy entering the season, so fantasy owners should have no reservations drafting McCoy as their RB1.  That goes double for PPR leagues.
• When using PPR, we see Sproles vault into the top ten on both a per-game and per-quarter basis.  And again, the two Denver running backs were both excellent in those splits, too.
• In non-PPR leagues, Alfred Morris is a less attractive pick.  Even with 13 touchdowns in 2012, he was only RB12 on a per-quarter basis in this scoring system. Frank Gore is another player who drops quite a bit once you include PPR and per-quarter production.
• Reggie Bush is a trendy pick this year, and I'm buying the hype: I think he'll excel working with Matthew Stafford and Calvin Johnson. That said, Bush was only RB20 in fantasy points per quarter last year, as he was already a huge part of his team's offense (which is why he ranked 14th in fantasy points).
• Danny Woodhead was a RB2 in PPR leagues on a per-quarter basis last year. If you think the Chargers might struggle in 2013, that might lead to Woodhead seeing the field a lot, he could be a solid flex play (or RB3) that you can get very late in your drafts. In any event, if you draft Ronnie Brown, I'd certainly handcuff Woodhead to him in PPR leagues.