ASHBURN, Va. – Washington Redskins coach Mike Shanahan says “right now it looks good” that Robert Griffin III will be able to play Sunday against the Minnesota Vikings.

Shanahan said Griffin was experiencing no dizziness, headaches or vomiting Monday, a day after the No. 2 overall draft pick suffered a concussion in a loss to the Atlanta Falcons.

News for two other NFL quarterbacks wasn’t as good Monday.

•Chiefs quarterback Matt Cassel suffered a concussion in the fourth quarter of Sunday and is unlikely to play in next weekend’s game at Tampa Bay.

•Tennessee quarterback Jake Locker will miss his second straight game with an injured left shoulder Thursday night when the Titans play the Pittsburgh Steelers. Shanahan emphasized that Griffin will have to go through a series of tests to satisfy the NFL’s return-to-play protocol. If there are any setbacks during the testing, the coach almost certainly will start Kirk Cousins or Rex Grossman against the Vikings.

Just joking

Wes Welker told reporters he was only joking when he said after Sunday’s game that he enjoyed catching 13 passes against the Denver Broncos to “stick it” in coach Bill Belichick’s face.

“It was a joke,” Welker said Monday. “I don’t know what else to say about it.”

Around the league

Arizona running back Ryan Williams is out for the season with a left shoulder injury that will require surgery. … The NFL suspended New York Giants rookie safety Will Hill for using Adderall. …

Pittsburgh safety Troy Polamalu will miss Thursday’s game against Tennessee after aggravating his strained right calf and linebacker LaMarr Woodley is doubtful with a mild right hamstring injury.