ARLINGTON, Texas -- Washington Redskins linebacker Brian Orakpo said after Monday night’s 18-16 loss to the Dallas Cowboys that he expected to be fine after suffering cramps that kept him sidelined off and on during the second half.

Orakpo hobbled off the field, was attended by trainers on the sideline and then was helped to the locker room, where he received intravenous fluids, coach Mike Shanahan said after the game.

With Orakpo out of the game, linebacker Rob Jackson delivered a hit on Tony Romo that forced a fumble, but the play was nullified by safety Oshiomogho Atogwe’s penalty for defensive holding.

Orakpo came back briefly, but Jackson ended the game at the right outside linebacker position.

Washington also lost receiver Anthony Armstrong , who suffered a hamstring injury in the first half. Shanahan said he wasn’t sure how serious Armstrong’s injury was.

Safety LaRon Landry, who made his season debut after missing the first two games with a strained hamstring, said that he felt fine after the game.

Landry started, recording four tackles and a forced fumble. He missed the first five plays of the second half after emerging from the locker room with the third quarter already in progress. Landry said after the game that was because he was receiving intravenous fluids during halftime..

Cornerback Josh Wilson was limited by a back injury in practice all week, but started and recorded four tackles, four pass breakups and a fumble recovery. Wilson said after the game that he was fine.