Robert Griffin III moved better on his sprained right knee at practice on Thursday but the Washington Redskins do not plan to announce their starting quarterback until Sunday, a team source told ESPN NFL Insider Adam Schefter.

"You could see he was more comfortable," coach Mike Shanahan said. "He was improved over yesterday."

Shanahan said Thursday that he plans to wait as long as possible to announce whether Griffin or backup Kirk Cousins will start. He didn't confirm the decision would come Sunday, only saying that "probably" will be the day he makes the call.

"We'll get a chance to see how Robert progresses during the week and make a decision, probably on game day," the coach said.

Griffin was officially listed as "limited" in practice. He stretched and made some basic throws during the 20 minutes the session was open to reporters. He was still favoring his right leg somewhat, but he was able to plant and throw more smoothly than he did on Wednesday.

At one point, Griffin pantomimed taking snaps to the side while Cousins and third-stringer Rex Grossman ran a drill.

"You've got to have a good feeling that he can play at full strength," Shanahan said. "If he can do that, then he will play."

Griffin has a mild sprain of the lateral collateral ligament in his right knee after getting hit from defensive tackle Haloti Ngata late in regulation in Washington's 31-28 overtime victory over the Baltimore Ravens.