Oakland Raiders can't explain why Amari Cooper was ineffective

ALAMEDA, Calif. -- Oakland Raiders rookie wide receiver Amari Cooper had the least productive game of his NFL career with one catch for 4 yards. His four targets were second to Michael Crabtree, who was thrown to 11 times and caught six passes for 50 yards.

Cooper dropped two more passes, giving him eight for the season by one statistical service. Cooper, who was battling a quad injury last week, got tight coverage from Detroit corner Darius Slay but the Raiders conceded he should have been more involved.

"I can't speak specifically to it," Del Rio said. "I think they tried to roll up on him a little bit. He ended up having just one ball. He dropped a couple. Obviously, he's a good player for us. We need to find ways to get him more involved."

Carr was also short on specifics.

"I'm not sure if you could say, 'It's this thing, or it's that thing,'" Carr said. "For whatever reason, he didn't get the balls, as many as he usually does. We'll go back and see why. I wish I had a better answer for you."

--As the Raiders struggled in the first half, one apparent first down on a pass from Derek Carr to Michael Crabtree was negated when officials ruled no catch because he lost the ball when he touched the ground after getting both feet in bounds.

It was debatable even by the NFL standard for a catch, so much so that former NFL official Mike Carey in the CBS booth said he thought the play had been ruled incorrectly.

Del Rio didn't challenge the play, even though he agreed with Carey.

"If we're playing in my backyard, then that's a catch, but I know how the league is going to call it," Del Rio said. "It doesn't matter if I agree with it or not, I know how they're going to call and it would have been a waste of a challenge."

NOTES: Tight end Lee Smith was inactive with a wrist injury, which, according to the CBS broadcast, needed surgery during the week, and is expected to play this week. ... Center Rodney Hudson, out the previous week with an ankle injury, played 32 snaps before reinjuring his right ankle in favor of Tony Bergstrom. ...Running back Taiwan Jones left with a knee injury and played just one snap on offense and two snaps on special teams as a gunner. ... Linebacker Ben Heeney played in nickel and dime defenses and had his most extensive playing time of the season with 38 snaps, second only to Malcolm Smith among Raiders linebackers.