What do we make of LeSean McCoy and DeMarco Murray. Both have had a lot of good seasons (including last year), but both will be 29 years old on opening day. When should we start downgrading players for age?

We know that backs can be effective at 29 and 30. That’s common. But we also know that the very best seasons for running backs are more likely to occur around the ages of 26 and 27. These guys are past that now.

So I’ve put together a little mini study. I’ve gone through the previous seasons since 2000. I’ve identified all running backs who had at least three 1,000-yard seasons by the time they turned 28. Then I’ve checked how those running backs played the season they were 29.

But before I list the numbers, I’m breaking the guys into two groups.

I’ll start with players who not only met those requirements but also ran for 1,000-plus at the age of 28. (Just like McCoy and Murray). The vast majority of these guys, in theory, should have been among the first 10 running backs chosen in fantasy drafts.

There are 18 who meet the requirements. Two totally knocked it out of the park, putting up difference-maker numbers: Priest Holmes and Tiki Barber. Three others finished with around 1,500 total yards and 10-12 TDs, which is solid enough. Three others were pretty good, and then it starts tailing off.

Adrian Peterson’s on there, but recall that was the year he was suspended for most of the season after the bizarre child discipline incident.

A few other backs weren’t even playing at age 29, and I’m not listing them (including Ricky Williams, Robert Smith, Travis Henry, Willie Parker and others).

29-YEAR-OLD RUNNING BACKS (A LIST)
YearPlayerRecRunTotalTD
2003Priest Holmes, K.C.6901,4202,11027
2004Tiki Barber, NYG5781,5182,09615
2008LaDainian Tomlinson, S.D.4261,1101,53612
2002Marshall Faulk, St.L.5379531,49010
2012Frank Gore, S.F.2341,2141,44810
2002Curtis Martin, NYJ3621,0941,4567
2007Edgerrin James, Ariz.2041,2221,4267
2015Matt Forte, Chi.3898981,2877
2012Steven Jackson, St.L.3211,0421,3634
2003Eddie George, Tenn.1631,0311,1945
2008Jamal Lewis, Clev.1781,0021,1804
2001Jerome Bettis, Pitt.481,0721,1204
2006Shaun Alexander, Sea.488969447
2005Fred Taylor, Jac.837878703
2015Marshawn Lynch, Sea.804174973
2015Arian Foster, Hou.2271633903
2012Cedric Benson, Cin.972483451
2014Adrian Peterson, Minn.1875930

There are other backs with similar qualifications, but they’re a little different. With these 10, the players didn’t run for 1,000 yards when they were 28. So expectations were generally a little lower for these guys.

One really good one – Corey Dillon killing it for New England. Stephen Davis had a very good year for Carolina. Ahman Green and Willis McGahee were OK. Then things really start dropping off.

29-YEAR-OLD RUNNING BACKS (B LIST)
YearPlayerRecRunTotalTD
2004Corey Dillon, N.E.1031,6351,73813
2003Stephen Davis, Car.1591,4441,6038
2006Ahman Green, G.B.3731,0591,4326
2011Willis McGahee, Den.511,1991,2505
2015Chris Johnson, Ariz.588148723
2004Duce Staley, Pitt.558308851
2008Deuce McAllister, N.O.1284185466
2010Clinton Portis, Wash.552272822
2014Maurice Jones-Drew, Oak.71961670
2016Jamaal Charles, K.C.1440541

So where does this leave us?

I think McCoy and Murray are good backs, but we’ve definitely seen their best ball. I don’t consider either to be a difference-maker type guy. Both are on teams that didn’t make the playoffs last year, and both are on rosters that include other capable running backs.

—Ian Allan