Robert Griffin III walked gingerly through the Washington Redskins' locker room, his sprained right knee in a big black brace.

Teammates stood at their lockers, mixing the emotions of an improbable 31-28 overtime win over the Baltimore Ravens with the fear that their franchise player could be seriously hurt.

"We're happy that we won, obviously," left tackle Trent Williams said. "But that is concerning, knowing he went down. Everyone wants to know how he's doing."

Griffin went down during Washington's final drive of regulation Sunday, with the Redskins trailing by eight. Fellow rookie Kirk Cousins, who had played in only one other game this season, stepped in and hit Pierre Garcon for an 11-yard touchdown pass with 29 seconds to go, then ran the quarterback draw for the two-point conversion to tie the game.

Yet another rookie, Richard Crawford, returned a punt 64 yards in overtime to set up Kai Forbath's 34-yard game-winning field goal. The Redskins (7-6) have a four-game winning streak - putting pressure on the New York Giants in the race for the NFC East title - but the day's most important result was still to come, with Griffin scheduled to undergo an MRI.

The worst-case scenario would be a season-ending ACL tear, like the one Griffin had while playing for Baylor in 2009.

"I'm not a doctor, but I know what an ACL feels like," he said. "And it doesn't feel like an ACL. I'm not too nervous, but I'll definitely be praying during the MRI."

With the Redskins trailing, 28-20, after Ray Rice's 7-yard TD run with 4:47 to play, Griffin started moving his team before he was tackled by Haloti Ngata at the end of a 13-yard scramble.

"I knew as soon as I got hit. I screamed. Like a man, of course," Griffin added with a laugh. "It hurt really bad."

Griffin left for one play, then returned for four more, completing two passes to get the Redskins deep into Ravens territory. But he was also hopping on one leg. Eventually, he fell to the turf and could no longer continue.

"I knew I needed to get out at that point," Griffin said. "I couldn't move."

In came fourth-round pick Cousins, who was a clutch 2-for-2 - back-to-back to Leonard Hankerson for 15 yards and to Garcon for 11.

The Ravens got the ball to start OT but went three-and-out. Crawford had the big return to Baltimore's 24, putting the 'Skins easily within the range of Forbath, whose 14-for-14 in his debut NFL season.