ASHBURN, Va. - Get ready for another week of RG3 guesswork.

Coach Mike Shanahan said Monday he's still waiting for a thumbs-up from the doctors before declaring that Robert Griffin III can return to game action.

The rookie quarterback sprained the lateral collateral ligament his right knee in last week's win over the Baltimore Ravens and missed Sunday's 38-21 victory over the Cleveland Browns.

"We're going to play Robert when he's 100 percent," said Shanahan, whose team visits the Eagles Sunday. "When that ligament's fine, when the doctors feel there's no chance for injury that he can go out there and perform at that level in a game situation without injury, we're going to go with our starter."

Shanahan waited until Saturday night to announce that backup Kirk Cousins would make the start and said he is taking the doctors' advice. Griffin immediately made it known that he was unhappy with the decision.

Meanwhile, Griffin's No. 10 jersey has sold more than any other player's in a single season since the NFL started keeping track 6 years ago, according to league spokeswoman Joanna Hunter.