BETHLEHEM, Pa. -- Eagles defensive end Trent Cole joins the growing list of injured defensive lineman, due to swelling in the acromioclavicular (AC) joint in his shoulder.  Head coach Andy Reid said it “could be a day, it could be a week,” to get Cole back on the field.

Cole, the only defensive end in the league with eight or more sacks in each of the last six years, was injured in practice on Monday but the injury wasn’t severe enough to report until Monday night.

The Eagles were off yesterday.

“We tried to get [the swelling] calmed down last night,” Reid said. “[We] came back this morning; it was swollen a little bit more this morning than it was even yesterday.”

Reid said Cole will be able to return as soon as the swelling goes down. Cole declined to comment at all on the injury, other than to say he’s always ready.

The Eagles are now without both of their starting defensive ends, as Jason Babin continues to recover from a calf strain that could keep him out the rest of the preseason, according to CSN Philly’s Reuben Frank.

Babin walked on a treadmill after the Eagles practiced today, but does not appear to be nearing his return.

That creates opportunities for players who will be fighting to make the team, or the active gameday roster, once Babin and Cole return.  Brandon Graham and Darryl Tapp will take the first team repetitions for now.

“I’m looking at it as a big thing, because I don’t want to have to deal with y’all guys if I don’t,” Graham said with a laugh.  “I’m going to be working hard, man, I’m really excited to go out there and just show what I can do.”

Graham, entering his third season and coming off a year in which he struggled to get onto the field as he rehabbed a knee injury, labeled himself a bust this offseason and set out to prove his worth.

Now he’ll get an extended chance to do just that.

“Everybody’s got to step up, you never know basically what’s going to happen,” Graham said.  “I’m just taking this time to really just enjoy the moment and show them that we’re not going to lose a beat just because a guy’s out.”

“We always preach every rep you get is an opportunity to show what you can do and be able to better yourself as a professional football player,” Reid said. “Another man gets hurt, it gives you an opportunity.”

In addition to being without their starting defensive ends, the Eagles came into training camp without the services of Mike Patterson, a starter at defensive tackle.  That leaves defensive tackle Cullen Jenkins as the only remaining healthy starter.

Patterson is likely to miss at least a month of regular season time as he recovers from offseason brain surgery, so the Birds are down three starters on the defensive line for the time being.

Derek Landri has been taking first team snaps in Patterson’s place, with Antonio Dixon and first round pick Fletcher Cox battling for time as well.  The Eagles typically rotate their top eight defensive lineman in the high octane system of defensive line coach Jim Washburn.

So while they’re confident in their depth moving up to the first string, the Eagles will also be giving more snaps to the likes of Phillip Hunt, Vinny Curry and Cedric Thornton with their second team.

The Eagles had high expectations for Curry, a second round pick, after the draft, but he too has been hampered by injury.

“Remember the high ankle sprain that he had, those things they tweak themselves as you go along for a month or two,” Reid said. “Working with that, he sure has done a nice job with his pass rush.  Very strong, you can see that, and he has great leverage.”

If Cole and Babin are back at full speed for the season opener and Patterson doesn’t miss too much time, the next few weeks will be remembered as a great opportunity for the Eagles to evaluate and develop their depth.

Of course, if there are setbacks, the Eagles defensive line could go from being a huge strength to a key weakness when they open their season on September 9.

For now, it’s a storyline that warrants attention as camp progresses.

Injury Report

Tight end Brent Celek (mild MCL sprain in right knee) was working out on the side as the Eagles went through their walk thru this morning.  Reid said he’s progressing, but is not yet ready to return.

Defensive end Jason Babin continues to rehab his calf strain, and is doing better, according to Reid.

Wide receiver Riley Cooper underwent surgery Monday to repair his fractured left collarbone and is expected to be out about six weeks.  Reid says he’s doing better and feeling more comfortable.

Safety Phillip Thomas (hamstring) is also improving, according to Reid.

Ryan Messick covers the Eagles for 97.3 ESPN FM.  Follow him on Twitter.