Player Points - Jahvid Best
By Chase Stuart
May 11th, 2010

Jahvid Best was a terrific player at the University of California and then ran a 4.35 40-yard dash at the NFL combine. There are two main doubts about him at the next level. Best dealt with nagging injuries early on at Cal, but then suffered two concussions during his junior year. The second concussion was particularly gruesome and it cost him the remainder of his college career. But the bigger doubts Best must overcome relate to his size; at 5'11, 199, some question whether he can be an elite fantasy player. Why is that? Over the past three seasons, only three sub-200 running backs have finished in the top 24: Chris Johnson, Jerome Harrison and Steve Slaton. Slaton looks like a one-year wonder and Harrison may end up being a one-month wonder; that leaves Chris Johnson and not much else when it comes to recent fantasy value by smaller backs. So are Best backers being duped by visions of Chris Johnson dancing in their head when the odds are that most backs his size won't make it?

Let's start by defining what "his size" actually means. It's a more complicated question that I initially thought. Maurice Jones-Drew is "only" 208 pounds but he packs that on a 5'7 frame; he has a BMI of 32.6, much "bigger" than that of the average running back. (BMI is a measure of size calculated by comparing a person's height and weight.) Darren McFadden is heavier than MJD, but at 6'2, 210, his BMI of 27.0 means he has a much lighter, leaner frame than Jones-Drew. On the other hand, there's something to be said for blunt force; a back that weighs 220 pounds can punish a defense much more than a back that weighs 195. In the end, both "weight" and BMI matter.

So how do we compare weight and BMI? There are many ways you could do it. Here's what I did:

  1. Recorded the weight and BMI of every running back with at least 100 carries over the past five seasons. I used a cut-off of 100 to make sure that I only included running backs who played on a semi-regular basis at a minimum.
  2. Measured the average weight and average BMI of the group, along with the standard deviation of both variables. The average weight was 218.2 pounds, with a standard deviation of 14.9 pounds. The average BMI was 30.4, with a standard deviation of 2.0. This means a running back would be one standard deviation heavier than average if he weighed 233.1 pounds, and he'd be one standard deviation below average if he weighed 203.3 pounds. Assuming a normal distribution, this also means that about 68% of all running backs in today's NFL that carry the ball at least 100 times in a season have a BMI of between 28.4 and 32.4.
  3. Assigned each running back a weight and a BMI grade on a scale where 100 was average, and every 15 points correlated to one standard deviation above/below average. Now that the two variables were on the same scale, I averaged the numbers, to assign a "size" grade to each running back.

Full disclaimer: Some of you will think steps two and three look like math gibberish. It mostly is. Unfortunately, a simple question like "which running backs are the biggest" has a complicated answer. While the math and the formula was complicated, the results match what any average football fan would know. Essentially, I'm just objectifying what we see when we watch the games.

But all of the above is just background information. Let's get to the point of the post. I looked at all running backs drafted inside of the first 50 picks (Best was the 30th pick in the 2010 draft) since 2000; I chose to exclude prior years because in earlier eras, running backs (and all players) were smaller. There were 42 such running backs; three of them did not play as rookies due to injury. In looking at the remaining 39 runners, I wanted to see if there was any correlation between size and fantasy value. The table below shows the year each running back was drafted, which draft pick was used on him, his BMI, height and weight as a rookie, and his rookie VBD number. The last three columns show the players scaled weight and BMI (with 85 being one standard deviation below average, 70 two standard deviations below, etc.) and finally, the last column is "size." Size is the average of the scaled weight and BMI categories, and is the variable by which the table is sorted.

Rookies
Tm
Year
Pick
BMI
Wt
Ht
RVBD
WT
BMI
SIZE
C.J. Spiller
BUF
2010
9
27.3
196
71
--
77
76
76
Jahvid Best
DET
2010
30
27.8
199
71
--
80
79
80
Ryan Mathews
SD
2010
12
29.6
218
72
--
99
93
96
Player
Tm
Year
Pick
BMI
Wt
Ht
RVBD
WT
BMI
SIZE
Tatum Bell
DEN
2004
41
26.5
190
71
0
71
69
70
Chris Johnson
TEN
2008
24
27.2
195
71
66
76
75
75
Reggie Bush
NOR
2006
2
27.1
200
72
46
81
74
78
Felix Jones
DAL
2008
22
27.1
200
72
0
81
74
78
Darren McFadden
OAK
2008
4
27.0
210
74
0
91
73
82
Trung Canidate
STL
2000
31
28.6
205
71
0
86
86
86
Adrian Peterson
MIN
2007
7
27.9
217
74
93
98
80
89
Joseph Addai
IND
2006
30
29.3
210
71
34
91
91
91
Donald Brown
IND
2009
27
29.3
210
71
0
91
91
91
Rashard Mendenhall
PIT
2008
23
29.3
210
71
0
91
91
91
Laurence Maroney
NWE
2006
21
29.3
210
71
0
91
91
91
William Green
CLE
2002
16
29.2
215
72
0
96
90
93
Julius Jones
DAL
2004
43
30.1
210
70
0
91
98
94
Matt Forte
CHI
2008
44
29.2
221
73
111
102
90
96
Marshawn Lynch
BUF
2007
12
30.0
215
71
31
96
97
96
Steven Jackson
STL
2004
24
28.6
229
75
0
110
86
98
Cadillac Williams
TAM
2005
5
30.3
217
71
12
98
99
98
Michael Bennett
MIN
2001
27
31.2
211
69
0
92
106
99
Knowshon Moreno
DEN
2009
12
30.8
215
70
18
96
103
100
Anthony Thomas
CHI
2001
38
29.3
228
74
45
109
91
100
DeAngelo Williams
CAR
2006
27
31.9
210
68
0
91
112
101
J.J. Arrington
ARI
2005
44
31.6
214
69
0
95
109
102
Chris J. Henry
TEN
2007
50
29.5
230
74
0
111
93
102
Chris Perry
CIN
2004
26
30.4
224
72
0
105
100
102
Larry Johnson
KAN
2003
27
30.1
228
73
0
109
97
103
Cedric Benson
CHI
2005
4
31.0
222
71
0
103
104
104
Thomas Jones
ARI
2000
7
31.6
220
70
0
101
109
105
LaDainian Tomlinson
SDG
2001
5
31.7
221
70
105
102
110
106
Kevin Jones
DET
2004
30
30.9
228
72
14
109
104
107
Shaun Alexander
SEA
2000
19
31.4
225
71
0
106
108
107
Deuce McAllister
NOR
2001
23
30.6
232
73
0
113
101
107
Chris Wells
ARI
2009
31
31.0
235
73
0
116
105
110
Ronnie Brown
MIA
2005
2
31.6
233
72
0
114
109
112
LenDale White
TEN
2006
45
30.8
240
74
0
121
103
112
LaMont Jordan
NYJ
2001
49
33.0
230
70
0
111
120
116
Jonathan Stewart
CAR
2008
13
32.8
235
71
0
116
118
117
Jamal Lewis
BAL
2000
5
33.5
240
71
34
121
124
123
T.J. Duckett
ATL
2002
18
34.4
254
72
0
135
131
133
Ron Dayne
NYG
2000
11
35.9
250
70
0
131
143
137
Kenny Irons
CIN
2007
49
27.9
200
71
--
81
80
81
Willis McGahee
BUF
2003
23
30.9
228
72
--
109
104
107
DeShaun Foster
CAR
2002
34
30.1
222
72
--
103
98
100

As you can see, Best has a size grade of 80. There's no denying the fact that Best is smaller than your average back -- quite a bit smaller, actually. But he was also a high draft pick. And has incredible speed. Sure, you don't see many successful backs as small as Best ... but you don't see many backs as small as Best get drafted in the first round and then bust, either.

And that's the point. Only five of the 39 running backs in the table above had a size grade of 85 or lower; two of them had VBD value as rookies. It's true that in the middle range, from 90 to 110, there have been eight successful rookie running backs. But there were 25 running backs drafted in that group, which means only one in every three were successful. That's pretty similar to the ratio for the tiny backs, too. When looking at Best, I think the right way to analyze him is not as a small back but as an incredibly fast back. And those guys are often successful as rookies, even if they're small. Yes, small backs don't usually make it in the NFL, but Best has already cleared the largest hurdle. By being good enough to be a late first round pick, Best should only be compared to similarly drafted players. And it's not like there's a long list of light-weight, first round running backs who didn't have fantasy value.

As for Best's long-term prospects, I think his size is a non-issue. When Ray Rice went to the NFL combine, he was 5'9, 195, similar to Best. Then he stopped being a student and started being an NFL player, and added 15 pounds of muscle to his frame in two years (he's now listed at 210 pounds). Clinton Portis was 5'11, 205 as a rookie, and dipped well below 200 pounds during his rookie season. Now he's listed at 221 pounds. Once Best bulks up to 5'11, 215, no one is going to question his size. I wouldn't worry about it for 2010, either.

Questions, suggestions and comments are always welcome to stuart@footballguys.com.