Sports

Eagles spiral through injuries, uncertainty in Kelly’s first season

PHILADELPHIA — The Chip Kelly Experiment promises to be the NFL’s most fascinating storyline this fall, but it’s off to a rough start.

Not only have the Eagles already lost one of their most important playmakers for the season to a knee injury, but the identity of their starting quarterback remains a mystery and their Pro Bowl running back keeps using words such as “confusing” and “different” to describe Kelly’s offense.

“It’s like night and day,” LeSean McCoy said.

The Eagles announced yesterday morning Donovan McNabb’s number will be retired Sept. 19 at home against former coach Andy Reid’s Chiefs. It took only a few seconds of watching practice yesterday afternoon to realize how completely Kelly has turned the page from those two longtime franchise icons.

Gone is Reid’s West Coast offense, replaced by the fast-break scheme Kelly used at Oregon that by all indications will be centered on the read option, which McCoy said “is definitely confusing at first.”

Long gone is McNabb, or any certainty at quarterback for that matter, replaced by the ongoing free-for-all between Michael Vick, Nick Foles, rookie Matt Barkley and Dennis Dixon.

Gone is any semblance of a typical NFL practice, replaced by what at times looks like a fire drill accompanied by a tackling ban and a blaring, non-stop musical score of rap, heavy metal and the “Pirates of the Caribbean” soundtrack.

Change can be good, of course, especially after a 4-12 season. But it has been a bumpy initiation for Kelly as the wildly successful college coach with no NFL experience tries to make the jump to pro football.

The Eagles lost star wideout Jeremy Maclin for the season to a torn knee ligament Saturday in a non-contact drill, and also will be without veteran special-teamer Jason Phillips after he suffered the same injury — on the same practice field in another non-contact situation, no less — yesterday.

While losing two vital players to torn ACLs in the span of three days would cast a pall over any team, the shock of the speedy Maclin’s sudden exit was still being felt yesterday — and promises to stay that way for a while.

“[Losing Maclin] definitely hurts,” McCoy said. “Anybody who tells you any different is crazy.”

What’s ironic about the injuries is Kelly’s practice system is designed to enhance his players’ safety. He even revealed yesterday the Eagles will not tackle at all in practice during training camp.

“No, we have four preseason games for [tackling],” Kelly said.

Who the No. 1 receiver is or whether the Eagles tackle in practice are just sideshows, though. The only question anyone here wants answered is the identity of the starting quarterback, even though that looks as if it will take a while.

Vick and Foles continue to split repetitions in practice, with neither emerging as the frontrunner. There is speculation Vick, 33, could be released if he doesn’t win the starting job, especially with Dixon, an option quarterback who played for Kelly at Oregon, also on the roster.

Kelly sounded yesterday as if all of his quarterbacks are starting from scratch — including Vick.

“Your resume is what you show us right now, so line up,” Kelly said. “Even if you were [drafted], that gives you no more precedent over someone else that was an undrafted free agent. The best guys are going to get on the field at every position.”

Four days and two huge injuries into camp, keeping them there has been Kelly’s biggest problem.

bhubbuch@nypost.com