When is a running back too old?

With all the talk recently about how many more good  years Brian Westbrook has left, I thought I'd take a closer look at running backs and age.

I put together a list of the top-five rushers in each of the past five seasons. Now I understand there's more to playing the position than rushing yards -- like blocking, catching the ball out of the backfield, etc. But I thought looking at their rushing yards would be the easiest way to figure out around what age range the league's elite backs tend to fall in.

Here's what I found:

Since 2003, there have been 16 different running backs who have finished in the top-five in rushing for a single season: LaDainian Tomlinson, Adrian Peterson, Brian Westbrook, Willie Parker, Jamal Lewis, Clinton Portis, Edgerrin James, Larry Johnson, Frank Gore, Tiki Barber, Steven Jackson, Shaun Alexander, Curtis Martin, Corey Dillon, Ahman Green, Deuce McAllister.

The average age for a  running back that finished the season in the top-five in rushing since 2003 has been about 26 years and seven months.

Note: Ages were not calculated to the exact day, but I did look at the months. Ages were calculated considering how old the running back was at the start of the season.

The oldest running backs to finish in the top-five in rushing during this stretch were Barber and Martin. Barber was over 31 when he rushed for 1,662 yards in 2006 and was over 30 when he rushed for 1,860 yards in 2005. Martin was over 31 when he ran for 1,697 yards in 2004. No other running backs who were 30 years or older at the start of the season finished in the top-five in rushing since 2003.

Westbrook will turn 29 right before this season starts. Other than Barber (who also rushed for 1,518 yards in 2004 when he was about 29 1/2) and Martin, the only other running back 29 or older to finish in the top five in a single season since 2003 was Dillon, who rushed for 1,635 yards while turning 30 during the 2004 season.

So there are the numbers. In the past five years, it has been unusual for older running backs to put together elite seasons rushing the football.

This post is not meant to say the Eagles should or shouldn't sign Westbrook, but rather to take a closer look at running backs and age.

What do you think?