Kenny Phillips, who has a long history of injuries, missed Tuesday's wet practice for what he said were precautionary reasons as he strengthens his left knee.

Phillips had microfracture surgery on his left knee in 2009. He's also battled injuries to his right knee. A source close to the safety said that the injury wasn't serious. Still, the fact that he has already missed a few practices bears watching.

Eagles coach Chip Kelly would only confirm earlier that Phillips missing practice was related to his knees and that his absence wasn't related to the rainy conditions.

But was it a setback?

"I don't ask questions," Kelly said. "They just tell me who's going and who's not going."

Phillips was signed as a free agent this offseason at relatively low cost. The Eagles were taking little risk on a player that has missed a number of games in his career because of knee issues. Phillips missed most of the 2009 season after surgery. He played in only seven games for the New York Giants last season because of an MCL sprain in his right knee.

Originally asked if Phillips had an injury, Kelly quipped, "Yeah, he's had an injury for a couple of years now."

Aside from Phillips, left guard Evan Mathis (ankle), tight end James Casey (knee) and linebacker Chris McCoy (knee) did not practice. Mathis and McCoy did some conditioning drills. Casey watched practice. Center Jason Kelce (knee) is still being eased into his return.

With Phillips out, David Sims took most of the repetitions at safety with the second team defense along with Kurt Coleman. Nate Allen and Patrick Chung were with the first team. Rookie Earl Wolff said he also took some snaps with the second team.