Is Karlos Williams sizing up to be the next to be hit by the dreaded sophomore slump? Teammates have been joking about the size of his waistline. Right now, he looks like last year’s Eddie Lacy. Eating too much, he’s conceded.

And it serves as a reminder that a big rookie season doesn’t guarantee a player will come in and rip it up or take the next step in Year No. 2. It’s not that easy.

Reality is, it’s tough to keep it going.

In the last 20 years, 23 rookies have averaged 5 yards per carry (with at least 50 carries), which is what Williams did last year. But all but three of those running backs averaged fewer yards the next year, and only 10 of the 23 came back in their second year and ran for more total yards.

Buffalo has plenty of other running backs. LeSean McCoy should be their opening day starter. Mike Gillislee was really impressive with limited touches last year, ripping off a lot of long runs. They’ve also drafted Jonathan Williams, who seemed like a second- or third-round prospect in the not too distant past at Arkansas, so can we say with certainty that Karlos Williams is even the best Williams on his own team?

Here are the second-year rushing stats for those sophomore runners (who all played really well in their first year). Guys who improved (ran for more yards) are in bold.

@table header:2 STANDOUT ROOKIE RUNNERS -- 2nd-year stats
Year Player Att Run Avg Diff 1998 Byron Hanspard, Atl. 0 0 --
2001 Mike Anderson, Den. 175 678 3.87 -809 2003 Clinton Portis, Den.Lee Suggs, Clev.Tatum Bell, Den.Steven Jackson, St.L.Mewelde Moore, Minn.Adrian Peterson, Minn.Jamaal Charles, K.C.Shonn Greene , NYJStevan Ridley, N.E.Andre Ellington , Ariz.—Ian Allan