Team spokesman Tony Wyllie said Sunday that Griffin underwent an MRI and has a sprained right knee but that "everything is clear" in terms of significant ligament damage.
Wyllie specifically ruled out a season-ending torn ACL.
Wyllie said Redskins coach Mike Shanahan will update the rookie quarterback's condition Monday. A league source told ESPN's Adam Schefter that there is "no guarantee" that Griffin will play next week against the Cleveland Browns.
Griffin was injured in the final minutes of regulation in the Redskins' 31-28 overtime win over the Baltimore Ravens. He had an X-ray at the stadium, and doctors poking at his knee told him that his ligaments "felt good."
"I'm not a doctor, but I know what an ACL feels like," Griffin said. "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."
"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. 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."
While he was being worked on by trainers on the sideline, Redskins backup quarterback Kirk Cousins entered and threw an 11-yard touchdown pass to Pierre Garcon with 29 seconds left. Cousins then ran in a 2-point conversion to tie the score 28-28, and the teams headed to overtime.
When Griffin departed, he was 15 for 26 for 246 yards and a touchdown pass. He also ran seven times for 34 yards.
"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."
It was the second game this season that the No. 2 overall draft pick has been unable to finish because of an injury. He left the Oct. 7 loss to the Atlanta Falcons because of a concussion, but returned the following week.
Information from ESPN's Adam Schefter and Sal Paolantonio and The Associated Press was used in this report.