The Washington Redskins proved they can win without Robert Griffin on Sunday, but their playoff hopes could take a hit if the quarterback is out for an extended period of time.

Team spokesman Tony Wyllie said after the game "everything is clear" in regard to ligament tears and that Griffin had an MRI and suffered a sprained knee. He also specifically said that Griffin did not sustain a season-ending injury

"I'm not a doctor, but I know what an ACL feels like," Griffin said to ESPN.com. "And it doesn't feel like an ACL. ... If I felt that, I'd be pretty nervous. But we won the game, everybody's praying for me, I feel pretty good right now about the whole situation. I'm not too nervous, but I'll definitely be praying during the MRI."

Griffin was hurt in the fourth quarter of Washington's 31-28 overtime win and it is "no guarantee" that he will be able to play next Sunday against the Cleveland Browns, sources told ESPN's Adam Schefter.

According to Fox Sports, "By medical definition, a sprained knee means that Griffin has some damage in at least one of the several ligaments in his knee."

Griffin tweeted following the game: ''Your positive vibes and prayers worked people!!!! To God be the Glory!''

Following a go-ahead touchdown by the Baltimore Ravens, Griffin was driving the Redskins down the field when he was tackled hard on a scramble by Haloti Ngata, who smashed into Griffin's knee on the play.

"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 limped off the field, but came back into the game after one play. He looked to be in massive pain and eventually left the game when it became too much.

"I knew I needed to get out at that point," Griffin said. "I couldn't move. At some point you have to do what's right for the team. And if I'm playing the rest of that game, I probably would have hurt myself even more."

Backup quarterback Kirk Cousins came into the game for Griffin and led the team on a game-tying drive by throwing an 11-yard touchdown to wide receiver Pierre Garcon with less than 30 seconds left. Cousins added a two-point conversion to tie the game at 28-28 and send it into overtime.

"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."

Cousins was drafted with Washington's fourth round pick in the 2012 Draft and proved on Sunday that he can handle an NFL offense. He came into a tough game against a tough team and performed well, completing two passes for 26 yards and one touchdown while helping to set up the game-winning kick in overtime.

"He's ice. Like they used to say about Larry Bird, he got ice water in his veins. That's the best thing you can say about Kirk," receiver Joshua Morgan said. "He was coming like nothing was even going on."

The real issue for the Redskins will be Griffin's health going forward. He had 246 yards and one touchdown on 15-of-26 passes before getting injured.

The team was 3-6 just a few weeks ago, but has won four-straight to remain in the playoff hunt. The Redskins are tied with the Dallas Cowboys in the NFC East and sit just one game behind the New York Giants for the division lead.

"We knew if we didn't get the win today, obviously those other three didn't mean a whole lot," Washington coach Mike Shanahan said. "I'm really proud of how the guys played."

Both the Cowboys and Giants won on Sunday, but New York has a tough schedule left against Atlanta and Baltimore, while the Redskins still have a game against Dallas that could help decide a playoff spot.

Earlier this season Griffin was injured against the Atlanta Falcons due to a concussion, but did not miss any further time. Last week Griffin engineered a comeback win over the New York Giants and set the single-season record for rushing yards by a rookie quarterback.

Griffin has been the most dynamic player in football this season and has helped to transform the attitude in Washington. He has passed for 2,906 yards and 18 touchdowns this season and has rushed for 748 yards and six touchdowns.

The Heisman Trophy winner would miss his first start this season if he cannot play against the Browns on Sunday. Cousins would be making the first start of his career.

"It's sore right now," Shanahan said after the game to Fox Sports. "He wanted to go back in the game, which is a good sign."