Jackson, a two-time Pro Bowl player, is slated to make $565,000 in base salary this season, the last on his four-year rookie deal. But he has expressed discontent about his contract on his Twitter feed.
His agent, Drew Rosenhaus, did not respond to an email, and Eagles general manager Howie Roseman said the team is going to "focus on the guys that are here."
When asked how disappointed he was that Jackson did not report, Roseman said, "We're going to keep that internal, and all conversations with DeSean we're going to keep private."
Jackson had 47 catches for 1,056 yards and six touchdowns last season, and his 22.5 yard-per-catch average led the league. He also averaged 11.6 yards on 20 punt returns, the most memorable a 65-yard scoring return on the final play of a come-from-behind 38-31 victory over the Giants on Dec. 19.
The win all but secured the NFC East title for Philadelphia, as New York was left out of the postseason.
The Eagles also announced that offensive tackle Winston Justice and defensive end Brandon Graham were placed on the Physically Unable to Perform list while recovering from knee injuries, and that wide receiver Jeremy Maclin and cornerback Asante Samuel had been excused from drills to attend to personal matters.
But the theme of Day 1 at Lehigh was more about the players who were not there: Jackson and Kevin Kolb, the backup quarterback who was finally dealt to Arizona in a long-awaited deal.
Jackson's absence wasn't much of a surprise, either. Especially not after Michael Vick hinted this might be the case, when he first met the media in Philadelphia on Tuesday.
"DeSean just has some things to think about," Vick said at the time, "and some decisions to make that only himself can make."
Coach Andy Reid did not seem concerned over Jackson's status during his first news conference Wednesday, and simply ran through his Thursday morning practice as a walkthrough. It was not open to the media or public.
Jackson was a key cog in the Eagles' offensive resurgence last season, as the team went 10-6 and formed a new identity around Vick.
"I'm just being realistic about the situation," Vick said. "It's all in what DeSean wants."
Copyright 2011 by The Associated Press