IN NEW ENGLAND, there is great concern over who is missing and whether they can get back, and get healthy, in time for that Super Bowl run that seemed predestined just a couple of games ago.

In Philadelphia, the concern is not so much about who is missing, but what is missing from the whos who are here. DeMarco Murray has gone from the NFL's leading rusher a season ago to the third back in a crowded backfield. Sam Bradford has managed the game better of late, but he is still far from the elite-level quarterback his draft status and early-career success suggested. Kiko Alonso, DeMeco Ryans, Mychal Kendricks, Jason Peters and Jason Kelce - each has taken their turns at horrifying us with their play this season.

But they have played. Through all kind of physical twists and turns. Kelce's left leg looks like a desert sunset. Peters is one awkward turn from another debilitating back spasm. And so on and so on.

Last year at this time Kelce said he had recovered from his sports hernia just fine. By the summertime, he admitted he was never 100 percent healthy from that hurt, and it clearly played its part in the Eagles' offense grinding to a halt in December. This season, Alonso and Ryans are running their hardest and trying their best, but those who have watched previous versions of each player - before their knee and Achilles' troubles - see a marked slowdown in each.

At his day-after press conference Monday, Chip Kelly spoke about overusing Alonso by involving him in 70 of New England's 86 offensive plays, a clear nod that the linebacker traded for LeSean McCoy is still hobbled by that knee he re-injured early this season.

As Kelly said Monday, an NFL truth is that, "There's no one that's anywhere close to where they started the season . . . your opponent is in the same situation.

"This game becomes which team can last the longest in a lot of aspects."

Here's the rub, though: A team that has a larger volume of such injuries has a larger volume of players limited or not involved at all in practice during the week. That makes it hard to fix the kind of mistakes the Eagles habitually make on Sundays, including the last one, when they committed seven penalties in the first half alone - five that were accepted.

There's also this: Players don't always come back to who they were from major injuries. Or even nagging, smaller ones. Often they learn a few years beyond the hurt how long it took to look like their old selves. And injuries of the kind Peters has, and Ryans had, and even Alonzo's major ACL repair, can alter a player's effectiveness permanently.

The Eagles are playing their wounded. They may even lead the league in that dubious category. And it continues to show. The offense scored 14 points on its own Sunday, about par with its performance against Miami, Tampa and Detroit. As devoid of talent that New England's offense was, Tom Brady still made those hobbled Eagles linebackers look slow. And as valiant as Ryans is and always will be, he may need this season to fully recover from the last.

The same might be true of Bradford. On Monday, Kelly praised his quarterback's game management and inferred that Bradford was getting more comfortable as the season wore on and the reps mounted. Bradford had completed 19 of 25 passes for 236 yards against Miami before he sustained the concussion (and non-throwing shoulder strain). He played possibly his best game in a 33-27 win against Dallas. He was just 14-for-24 against the Patriots and his longest completion was for 20 yards, but as Kelly noted, the three touchdowns scored by the defense and special teams kept the ball out of his hands for long chunks of that game.

And his team never trailed during the entire second half. "Sometimes the progress isn't exactly what you thought it would be," said Kelly. "It doesn't always go up. It depends on the individual's health."

The same thing applies to fatigue. You can play through it in football, pitch through it in baseball, still skate your wing in hockey. You just don't look as effective out there as you once did. Remember Cole Hamels' tired arm in 2009? Even his greatest critics back then - many who continually questioned his guts - should concede by now they got that wrong.

That may be precisely what's wrong with Murray. His inability to create positive yardage with any degree of consistency, especially in contrast to the effectiveness of other backs in this offense, has created, possibly for the first time in his career, a debate about his commitment and character. More than likely it has to do with the toll from last season's workload, a toll that was evident during the Cowboys' final games of 2014.

It may not be until next season that we see in Bradford, Alonso and Murray what we expected to see this season. Whether we see it in midnight green or some other team's color, though, is likely to depend on how close they can get to their old selves in the critical weeks ahead.

On Twitter: @samdonnellon

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