Raiders WR Duke Calhoun and rookie LB Mario Kurn suffered right knee injuries Saturday during practice. The prognosis doesn't look good for either player.

“Both look to be significant,” Raiders coach Dennis Allen said. “They’ll have to go through the process of being MRI'd but they look to be significant. We'll see.”

Calhoun, who played eight games for the Giants in 2010, was hurt while making a cut. He had to be carted off the field and into the locker room. Kurn, an undrafted rookie from San Diego, was helped off the field after being hurt but was able to walk on his own to the locker room

Myers update: Tests on TE Brandon Myers’ injured shoulder were negative. “That's one of the few times you ever hear negative and think it's good," Allen said. "But that was a good thing. He's a little sore today. We'll evaluate him the next couple of days and see where he's at come game day.” Myers was a spectator at practice.

Concern for Curry: Injured OLB Aaron Curry has yet to return from Los Angeles, where he was scheduled to have his injured knees examined by a specialist. Curry was injured during offseason workouts and was placed on the PUP list when he reported for camp.

Allen was asked if Curry was close to the point where he wouldn’t have time to get ready for the Sept. 10 regular-season opener against San Diego.

“We're getting closer to that point,” Allen said. “I don't know exactly where that is. Obviously he was not the same healthy Aaron Curry that we saw on tape last year. We're trying to do everything we can to give him a chance to get healthy so he can be out there opening night. We're getting closer to that point where that might not be a possibility but it's not there yet.”

Extra points: WR Denarius Moore (hamstring), WR Eddie McGee (hamstring), RB Taiwan Jones (hamstring), P Shane Lechler (knee) and OT Zach Hurd (head) missed practice and will all but certainly miss Monday night’s game. … DT Richard Seymour (knee), DE Jack Crawford (foot) and SS Tyvon Branch (back) returned to practice.

Follow Raiders reporter Eric Gilmore on Twitter: @CBSSportsNFLOAK.