PHILADELPHIA (973espn.com) — Three different players were missing this week as the Eagles started Phase 1 of their offseason work, Pro Bowl defensive tackle Fletcher Cox, veteran left tackle Jason Peters, and aging running back Darren Sproles.

Because the workouts, which are limited to strength and conditioning or rehab for injured players, are "voluntary," none of the players are required to be at the NovaCare Complex but absences usually signal something and that's probably the case with both Cox, who is  in line for a new big-money deal, as well as Peters, who ostensibly is still penciled in as the starting left tackle although the organization has clearly started to think about life after Jason.

Sproles, on the other hand, got the Eagles' permission to work out in California where he is helping to coach his child's track team, according to Philly Voice reporter and Sports Bash regular Jimmy Kempski.

Because the Eagles have a new coach, they, and every other team who made a change at the top, were permitted to start their offseason work two weeks earlier and having 68 of the 71 players under contract participating is a solid percentage.

Next up is the teams pre-draft voluntary mini-camp, which starts on April 19 and can feature some on-field work as the new staff begins implementing its systems and principles.

If Cox and Peters are not back by then, although not catastrophic by any means, it does probably signal they are each trying to send a message,

In Cox's case the Eagles have spent a lot of their offseason identifying core pieces and extending them but the Mississippi State product, who is unquestionably the club's best player, has yet to get his extension.

That said, his negotiations with Cox shape up as far more difficult because the star DT is already set to make significant money this season ($7.8 million) and if he has another big year Cox could really break the bank, a reality that Howie Roseman hasn't run from that fact.

“We talked about Fletch, he’s still on our to-do list, there’s no question about that," Roseman said earlier this offseason. "We’re not forgetting about that or him.”

The Eagles have currently pegged Cox's worth at somewhere between $12 million and $14 million a year but if you look at the success new defensive coordinator Jim Schwartz has had with under tackles in his 4-3 scheme, Cox's projected position, that number could rise significantly after the 2016 season if Cox feels like betting on himself.

With most of their work in free agency done, the Eagles are currently $10.8 million under the cap, according to NFLPA figures. And that's where the inventive Roseman comes in because both Cox and the rookie class remain on deck.

“We have to make sure that we’re always in a place to be able to get Fletcher done,” Roseman said. “So anything we do, it’s in the back of our mind that we want to get Fletcher done. Whether that’s today, tomorrow, whatever point in time, we want Fletcher to be here.”

As for Peters, the Eagles clearly want him around for next season but that might be it despite the fact that he's under contract through 2018.The eight-time Pro Bowl selection turned 34 back in January and the injuries have begun to pile up.

A nearly $10 million cap hit this season has seemingly been rubber-stamped by Roseman but that rises to over $11 million over the next two seasons and Peters likely sees the writing on the wall so expect a guy who is going to be  marching to his own drum.

-John McMullen covers the Eagles and the NFL for 973ESPN.com. You can reach him at jmcmullen44@gmail.com or on Twitter @JFMcMullen