Darren Sproles and Fletcher Cox were absent from the Eagles’ OTA practice Monday at the NovaCare Complex.

The workouts are technically voluntary, although most players do attend.

There was no explanation from the Eagles regarding the absences. They could conceivably be injury-related, although that’s unlikely because they’d probably be outside with the trainers if they were hurt.

Head coach Chip Kelly isn’t available to the media until Tuesday afternoon.

Two-time Pro Bowl guard Evan Mathis also continues to skip the voluntary workouts. He hasn’t participated in any of them so far as he seeks a new contract.

Meanwhile, Earl Wolff participated in warm-ups and some individual drills, his first known work at any practice since he underwent micro-fracture surgery last November.

Wolff is in the mix for the second starting safety spot opposite Malcolm Jenkins but hasn’t really been healthy since first getting hurt late in his rookie year. He has seven career starts, six of them in 2013.

Second-year linebacker Marcus Smith, who has been absent from OTAs so far with a minor groin injury, also returned to practice Monday and appeared to be participating in most drills.

Also, Sam Bradford, coming off two season-ending ACL surgeries, was seen running in warm-ups for the first time, which would be considered a small but significant step for the projected starting quarterback.

With Allen Barbre working at Mathis' left guard spot, Matt Tobin and Andrew Gardner have been seen practicing with the first team at right guard, but veteran Dennis Kelly got some work with the starting group Monday.