PHILADELPHIA (973espn.com) - The Eagles began on-field preparations for the Oakland Raiders with two key defensive players watching.

Pro Bowl alternate Jalen Mills and rookie defensive end Derek Barnett were spectators as the Eagles went through stretching and individual drills. Barnett has been dealing with a groin issue of late while Mills' status will be revealed on the injury report.

In better news, slot cornerback Patrick Robinson (concussion) was on the practice field, although it's unclear if he has been fully cleared through the NFL's concussion protocol. It is, however, a good sign that Robinson will be available on Monday night.

Starting left guard Stefen Wisniewski (right ankle) was also participating on at least a limited basis Thursday after missing last Sunday's game against the New York Giants.

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