Counting the Bills: Running backs

Continuing a series analyzing the economics of the Buffalo Bills roster, position by position:

Position: Running back

Total cap value: $12,988,332

Compared to NFL average: 53.7 percent more

NFL positional rank: 4th

Portion of Bills' total cap number: 9.4 percent

2014 cap numbers:

C.J. Spiller: $5.916 million (5th on Bills, 9th among NFL running backs)

Fred Jackson: $3.85 million (Bills: 9th; NFL: 16th)

Anthony Dixon: $1.016 million (Bills: 30th; NFL: 55th)

Bryce Brown: $570,000 (Bills: tied for 47th; NFL: tied for 102nd)

Frank Summers: $570,000 (Bills: tied for 47th; NFL: tied for 102nd)

Evan Rodriguez: $570,000 (Bills: tied for 47th; NFL: tied for 102nd)

Ronnie Wingo: $495,000 (Bills: tied for 59th; NFL: tied for 158th)

Average per year:

Spiller: $5.219 million (6th on Bills, 10th among NFL running backs)

Jackson: $4.35 million (Bills: 9th; NFL: 12th)

Dixon: $1.166 million (Bills: 27th; NFL: 45th)

Summers: $570,000 (Bills: 51st; NFL: tied for 120th)

Brown: $537,720 (Bills: 57th; NFL: 149th)

Rodriguez: $525,000 (Bills: 59th; NFL: tied for 151st)

Wingo: $495,000 (Bills: tied for 77th; NFL: tied for 209th)

Most overpaid: Spiller. This is probably more of a commentary on the state of the running back position in the NFL more than it is on Spiller. Teams aren't giving running backs large contracts these days. Currently, Spiller's cap number is 416 percent higher than the NFL average at his position. Among Bills players, only Mario Williams has a larger gap from his positional average. This all sets the table for the Bills' upcoming negotiations with Spiller, who can become a free agent after this season. Are the Bills willing to pay Spiller top-five money for his position? Or can they get by with a rotation of younger players? I think the Bills would love to have Spiller's speed and big-play ability around for several more years, but he might still need to prove that he can be the lead horse in the backfield. He's not Adrian Peterson.

Most underpaid: None. This will likely be the final year that the Bills have this much cap space tied up in their running backs. At 33, Jackson isn't going to command the same deal that he received in 2012. Even though Jackson's production hasn't declined -- if anything, he's coming off one of his best seasons -- the Bills will need to consider the future with Jackson, not the past. Will he be worth $4 million a year or more as a 35-year old back? That's unlikely. If the Bills re-sign Spiller, there might be less willingness to bring back Jackson. I think the Bills would like Brown to develop into one of their lead backs, and if that happens, then he'll be underpaid. But for right now, there's no player worthy of that distinction.