BETHLEHEM, Pa. - Dennis Kelly has been a backup tackle through the first week of camp, so naturally he started Thursday as a guard and finished as a first-team tackle. This is life in training camp, when injuries accumulate and players down the depth chart must demonstrate that they can help the team in different ways.

"I'm working on it," Kelly said. "I think if you know one position, you should know all positions, if someone's helping you or not. It does make it a little easier, but when you put it in action it's a little different."

In the morning walk-through, Evan Mathis' illness forced the Eagles to juggle their line, and Kelly shifted over to guard. But his most important work came during the afternoon practice, when Todd Herremans' absence with a shoulder injury prompted the Eagles to entrust Kelly, a fifth-round pick, to protect Michael Vick's blind side.

Of course, Vick wore a red jersey that keeps defenders from hitting him. And it is premature to determine what the Eagles will do if Herremans were injured during the season. But Kelly, who is 6-foot-8 and 321 pounds, is at least earning meaningful training-camp snaps.

There were questions when the Eagles picked Kelly about whether he fits offensive line coach Howard Mudd's system. Kelly visited Philadelphia before the draft and had a lengthy meeting with Mudd.

"He told me my flaws and also told me some things that he really liked," Kelly said. "He thinks that I could really be a good player, so when he says something like that, I really took it to heart."

Play of the day

Jaiquawn Jarrett is determined to prove he's more than a big hitter, and he flashed some coverage skills Thursday. Vick rolled out to his left and launched a deep pass near the end zone for DeSean Jackson. Jarrett, who was the safety help, came over and broke up the play. The pass was a bit underthrown, but Jarrett still made up ground and halted what would have been a scoring play.

The other finalists included Jeremy Maclin's diving catch on a pass from Vick, and Bryce Brown showing some burst on a run up the middle.

Quote of the day

All four of the projected defensive-line starters - Cullen Jenkins and Mike Patterson at defensive tackle, Trent Cole and Jason Babin at ends - were sidelined for practice. It prompted Jenkins to wonder if the unit should meet in a different place.

"We can have our D-line meetings in the training room," Jenkins said.

Birds brains

Despite the humidity, the Eagles drew 8,427 to camp on Thursday. That is the largest crowd of the summer. The quarterbacks signed autographs, which contributed to the large number. . . . The running backs and linebackers will sign autographs after Friday's 2:45 p.m. practice.