Defensive tackle William Joseph was not present for stretching and preliminary drill work with the defensive line, indicating he may be the victim following the trade for the Patriots Richard Seymour.
The Raiders have not announced any transactions, either on their Web page or through their Twitter account.
Among the players who appear to have resurfaced in the practice squad include linebacker Slade Norris, a fourth-round pick. Also back are defensive end Greyson Gunheim, wide receiver Jonathan Holland, linebacker David Nixon and safety Jerome Boyd.
There was also a No. 45 who may or may not be fullback Marcel Reece.
Injured players who were not present as practice began included linebacker Isaiah Ekejiuba, wide receiver Chaz Schilens and running back Justin Fargas.
Cornerback Nnamdi Asomugha was practicing with his left wrist in a soft cast, Kirk Morrison with his left elbow in a brace. Also on the field were strong safety Mike Mitchell and tackle Khalif Barnes.
Punter Shane Lechler, who missed the final preseason game with a groin strain, was taking part in kicking drills.