LANDOVER, Md. -- After taking a shot to his helmet while scrambling to avoid a sack, Washington Redskins quarterback Robert Griffin III stayed facedown for a few moments Sunday, then eventually staggered to his feet with what doctors determined was a concussion.
For Griffin, who also was treated for a cut on his chin after the third-and-goal play, the game was over about 10 minutes into the second half of Washington's 24-17 loss to the Atlanta Falcons.
It was exactly the sort of thing everyone around the Redskins has been worrying about with the aggressive Heisman Trophy winner, the No. 2 draft pick in April.
"He wasn't sure what quarter it was in the third quarter. So at that time, when he wasn't really sure what the score was, what the quarter was, we knew he had a mild concussion -- at least according to the doctors," Redskins coach Mike Shanahan said after his team fell to 2-3. "It feels good right now; a lot better right now. But that was ... why he didn't go back into the game."
Team spokesman Tony Wyllie said Griffin was examined by a neurologist in the locker room before being sent home from the team's stadium. Griffin will be re-evaluated again Monday.
About three hours after the game, Griffin tweeted: "I'm ok and I think after all the testing I will play next week."
NFL rules require a player who has been diagnosed by the team medical staff as having a concussion to sit out the rest of the game. He also can't return to practice or game action until a team doctor and independent neurologist clear him.
The NFL will review how the Redskins handled the release of information surrounding Griffin's concussion, league spokesman Greg Aiello told NFL.com. NFL rules mandate timely and accurate reporting by teams when they release injury information, and the Redskins' initial description that Griffin was "shaken up" might not meet those standards.
"I knew it was a big hit, and I knew after he lay down that something was wrong," Redskins running back Alfred Morris said. "So I was like, 'Oh, no.' I said a prayer for him."
Added Redskins linebacker Lorenzo Alexander: "Obviously, it's a scary situation. Never want to rush a guy back like that. ... Hopefully Robert's able to get back as quick as possible, but only when he's completely healthy. Because once you get one concussion, they can occur rapidly if you go out there too soon."
Griffin was not in the locker room after Washington's eighth consecutive home loss.
Griffin was injured early in the second half, with the score tied at 7, while trying to scramble for the end zone on third-and-goal from the 3. As he went down, he took a solid hit to the helmet from the upper body of Falcons linebacker Sean Weatherspoon.
As Griffin was led off the field by trainers, chants of "RG3! RG3!" rang from the stands.
"I felt like he was still turning upfield, so I was just trying to make a play. Most quarterbacks would probably slide out of bounds or run out of bounds, but he's a tough guy," Weatherspoon said. "He's a tough guy, and I think he'll learn a little bit."
Griffin's injury came after his running had been scaled back.
Through Week 4, thanks in part to using some option plays, he was the league's top rushing quarterback with 234 yards, and already had tied a Redskins season record for a quarterback with four touchdowns rushing.
But against the Falcons, Griffin's only run was a 7-yard gain on a scramble. He was 10 for 15 for 91 yards passing.
"It's a different dynamic when he's not in there. You don't have to account for the quarterback running the football," Falcons coach Mike Smith said. "He's a distributor who throws it and hands it off to someone else, so it did change our game plan when he left the game."
On the play after Griffin was injured, the Redskins took a 10-7 lead on a 23-yard field goal by Billy Cundiff, who had missed four of his five previous kicks, including pushing a 31-yarder wide right in the second quarter Sunday.
Another rookie quarterback, fourth-round pick Kirk Cousins, took over for Griffin on Washington's next possession.
"I did get a word from a trainer that I would be going in and I would be finishing the game," Cousins said.
On his first snap in the NFL, Cousins completed a 4-yard pass to Joshua Morgan, before the Redskins wound going three-and-out and punting. On Cousin's second drive, he completed a 77-yard touchdown pass to Santana Moss to give Washington a 17-14 lead. But Cousins was intercepted on each of Washington's final two possessions.
The Redskins would like to see Griffin back under center next weekend against the visiting Minnesota Vikings, but perhaps with a slightly more cautious approach on plays like the one that sent him home Sunday.
"You'd like to have him throw the ball away when he's outside the pocket and not have to take that hit like that," Redskins linebacker London Fletcher said. "But he's a competitor, he's trying to make plays, so you can't fault him for that. But we're definitely concerned. Hopefully he'll be able to bounce back."
Information from The Associated Press was used in this report.