Robert Griffin III will have more tests on his injured right knee after hobbling out of Washington's first-round playoff loss to Seattle on Sunday.
Mike Shanahan. the Redskins coach, confirmed Griffin would travel to Alabama, to consult orthopaedic specialist James Andrews.
Shanahan said doctors need to distinguish between old and new problems, since Griffin had prior ligament injuries in the knee.
The sensational young star hurt his knee in a regular-season game against Baltimore, although he returned to that contest briefly before sitting out the following week.
He returned to action for the regular-season finale, a 28-18 win over Dallas, although he was clearly not 100 per cent, and he wore a brace on the knee for Sunday's first-round playoff game.
Griffin appeared to aggravate the injury in the first quarter on Sunday, and was down for several minutes after his right leg buckled oddly under him in the fourth quarter.
He eventually rose and limped to the sideline under his own steam and Shanahan stressed Monday that the severity of the injury was not yet known and that "everything right now is total speculation".
While postgame pundits were busy questioning whether Shanahan should have taken Griffin out of the contest sooner, the player himself said he didn't want to leave.
"You respect authority. And I respect Coach Shanahan," Griffin said after the match.
"But at the same time, you have to step up and be a man sometimes and there was no way I was coming out of the game."
Meanwhile Seattle will have to continue their NFL postseason campaign without Chris Clemons, who tore a knee ligament in the Seahawks' first-round win over the Washington Redskins.
Pete Carroll, the Seahawks' head coach, confirmed last night that the defensive end tore the anterior cruciate ligament and meniscus in the game against Washington.
"He will have to have surgery," Carroll said.
"So we'll miss him, which is a big loss for us in a lot of ways. Chris has been a great football player. He's been just a symbol of consistency for the years we've had him.
"He's been a great leader for us, too, and just a tough dude."
Clemons, 31, recorded a team-best 11 1/2 sacks this season and his absence will be felt when the Seahawks travel to Atlanta to face the National Conference top seeds Atlanta on Sunday in the second round of the playoffs.
Follow us @SprtNationalUAE