RICHMOND, Va. — The Washington Redskins have placed linebacker Trent Murphy on injured reserve with a torn ACL and MCL in his left knee, and signed Jamari Staples to bolster their injury-depleted wide receiver corps.

Murphy, the Redskins' top draft choice in 2014, was hurt in their 23-3 loss to Baltimore in their preseason opener on Thursday night.

"It's too bad," coach Jay Gruden said before practice Saturday. "He was really having a great off-season then he followed it up with a really good training camp so far. It's unfortunate, you know, just wrong place at the wrong time."

Safety Su'a Cravens also sustained a knee injury in the game, but is considered day to day.

"We're going to just keep a close eye on it and go day by day with this thing," the coach said. "See how it does the next couple of days, get the swelling out of there and see if he can practice."

The team also waived injured offensive tackle Kevin Bowen.