JaCorey Shepherd injury proving Cary Williams' point?

THE MOST interesting charge leveled at Chip Kelly this offseason had nothing to do with race. That honor belongs to former Eagle Cary Williams' suggestion that he and his teammates were "exhausted" toward the end of the year due to the coach's unapologetically intense practices.

Whether or not Williams' summation is accurate, it is worth mentioning in connection with something that happened midway through yesterday's open practice at Lincoln Financial Field. At the end of a nifty catch-and-run, running back Darren Sproles collided with JaCorey Shepherd, knocking the cornerback awkwardly to the turf, where he remained for several minutes before being carted off by the training staff with an apparent leg injury. (A team source told the Daily News' Les Bowen there is some concern about his ACL.) The team has not given any indication about the severity of the injury, except to say that Shepherd will undergo an MRI today.

But even if the incident proves to be nothing more than a scare, it offers a fitting reminder that a team's success often has as much to do with the health of its players as it does the execution of a coach's scheme. And despite the considerable time and resources Kelly spends on his sports-science wizardry, we still don't know if he has a firm handle on what it takes to make it through an NFL season with the requisite number of healthy bodies.

The remarks by Williams - now with the Seahawks - are relevant to the discussion in several regards. First, there is his implication that Kelly's practice methods might reach a point of counterproductivity with regard to the physical fitness they are supposed to create. There is a fine line between conditioning and overtraining, and there isn't a computer program or urine sample in the world that can allow a coach to feel a player's muscles, joints and psyche the way the player himself feels them. A fatigued athlete is an athlete who is more susceptible to injury, even if the fatigue is more mental than physical. Ask anybody who plays pickup basketball: You always get hurt in that sloppy final game.

While the circumstances that resulted in Shepherd's injury yesterday are not unique to Eagles training camp, the sheer volume of those circumstances in each practice is greater, which would seem to create more opportunities for those circumstances to conspire to create an injury. Kelly will tell you that his key players do not get any more reps than they would with other teams - rather, it is the backups who get more than their counterparts on other teams. But if that is the case, the speed and intensity with which those reps are performed is much different than it is with other teams. It is worth noting that Shepherd's injury occurred at the end of the play, when the rookie appeared to be slowing up while Sproles appeared to be going full speed.

On the other hand, there is no evidence that the Eagles have suffered an inordinate amount of practice injuries under Kelly. In fact, health was one of the biggest factors in the division title he won his first year, with Jeremy Maclin the only significant casualty. Last year was a different story, with Todd Herremans, DeMeco Ryans, Earl Wolff and Evan Mathis all going on injured reserve. But again, that's not much different from Andy Reid's last season, when Herremans, DeSean Jackson, Jason Peters and Jason Kelce all spent time on IR.

I'm inclined to think that any negative impact of Kelly's methods is more likely to be chronic than acute, which is why the Shepherd situation might be more relevant to Williams' comments on an abstract level. See, Shepherd was on the field because Brandon Boykin wasn't - Kelly traded him to the Steelers for a conditional fifth-round draft pick, in large part because he liked what he saw of Shepherd during OTAs. Now, neither of them is on the field. If the injury to Shepherd turns out to be serious, the Eagles will be two cornerbacks down from where they were just two weeks ago.

In trading Boykin, Kelly not only diminished the talent level of the top of the depth chart, he also brought the bottom of it one step closer to having to play. That doesn't make the trade ill-advised, provided he has an accurate gauge on the attrition rate of a 53-man roster over the course of an NFL season as well as the attrition rate of the bodies of each of those 53 men. But if he has underestimated the number of qualified players that he needs, or the impact that his practices can have on the human body, then he could easily arrive at Week 17 wishing he had another healthy cornerback or guard lying around.

From what we know about Kelly, there's a pretty good chance he has thought all of this stuff through. But human beings have been trying to control the health of their bodies for as long as the species has existed, and they have spent just as long realizing the limits of their efforts. Like so much else about Kelly, we won't be able to judge the efficacy of his attempts until his time in the NFL is done, at which point they will have resulted in the sustained success he has sought, or they will have not.

We know where Williams stands.

Blog: ph.ly/HighCheese