LeSean McCoy is still just 25 years old (he'll turn 26 in July), and he is a huge piece of the Eagles' core of young players. However, surprisingly, he's one of the most experienced starting running backs in the NFL.
I projected the starting running backs for 30 teams, omitting the Browns and Raiders, who don't have a running back currently on their roster who should be starting in the NFL. I then added in 6 free agents who could start for whatever team they land on, for a total of 36 running backs. Only 12 of those 36 backs have been in the league longer than LeSean McCoy. Here is the year each of those backs entered the league, from oldest to most recent:
That is the nature of the RB position in the modern NFL. Running backs get chewed up and spit out, with few runners remaining effective for much more than 5 years.
During the span of his first 4 years in the NFL, from 2009 to 2012, McCoy ranked 9th in total touches among NFL running backs:
If you take a look at the 8 RBs ahead of McCoy in total touches in the chart above, 7 of them have been around longer than McCoy. With the exception of Matt Forte, all of them saw a decline of at least a half yard in yards per carry from their career average to their yards per carry average in 2013:
Last season in Chip Kelly's run heavy offense, LeSean McCoy led the NFL in rushing attempts and total touches from scrimmage:
Nobody is predicting any sort of immediate decline in LeSean McCoy's play, nor should they, but if he touches the ball 350 times every season, that is going to take a toll on McCoy's body. Three things to note:
1) Appreciate watching McCoy while he's still at the top of his game.
2) When teams are flush with depth at one position or another, it is somewhat logical to think about trading some of that depth for assets that can strengthen other position. Therefore, there are a number of fans who wouldn't mind seeing Bryce Brown traded. Unless there's a really good return, and even if they're high on Chris Polk, the Eagles should be in no rush to trade Bryce Brown,
3) LeSean McCoy is widely considered a top 3 RB in the NFL and taking him off the field when you're in the heat of the moment seems crazy at times. However, the Eagles really should consider ways they can begin working in Brown and Polk more often to lighten McCoy's load, so he can continue to be the elite player he is for years to come.