Eagles defensive end Brandon Graham underwent microfracture surgery on his right knee in December after he tore his anterior cruciate ligament against the Cowboys on Dec. 12, sources have confirmed.

Graham also confirmed the report, first made by AnnArbor.com, through a text message, but declined further comment.

He later wrote on Twitter, "I am not doing interviews with nobody until I'm back on the field. Everybody needs to worry about this lockout if anything. I got this!!"

During the operation to repair Graham's ACL it was decided that microfracture surgery, considered by many knee experts to be a more serious procedure, was necessary. The Eagles announced that the ACL procedure was a success following the operation but made no mention of microfracture surgery.

The team had no comment on Wednesday.

Eagles coach Andy Reid has said as far back as March that it would be "a real stretch" for Graham to be back by the season opener. Last month during a chat with The Inquirer Reid was asked again if Graham would be back by the start of the season.

"Probably not," he responded.

Graham, the Eagles' 2010 No. 1 draft pick, could potentially miss much more than just the opener. He recently told reporters in Ann Arbor, while he was participating in a golf outing, that he was 80 percent recovered, though.

Victor Abiamiri, of course, was the last Eagles player to undergo microfracture knee surgery. The Eagles defensive end, the team's second-round pick in 2008, had the procedure in Feb. 2010 and missed all of last season. He recently said that he was fully recovered and would be ready for the coming season.

Graham has spent most of the off-season rehabbing in Southern California. Despite the NFL lockout the Eagles have been permitted to receive updates on his recovery.

In his rookie season Graham recorded three sacks and 19 tackles in 13 games before he was lost for the season. Despite his condition the Eagles did not select a defensive end in the draft. They still have free agency, however, to address the need.

Trent Cole and Juqua Parker started most of last season and both are slated to return next season, as are reserves Darryl Tapp, Daniel Te'o-Nesheim and Ricky Sapp. The Eagles also added Canadian Football League product Phillip Hunt in the off-season.