Washington Redskins quarterback Robert Griffin III was at team headquarters Monday and reported no ill effects from the third-quarter concussion that knocked him out of the team’s 24-17 loss to the Atlanta Falcons Sunday, Coach Mike Shanahan said.

Shanahan said he and Griffin spent roughly 20 minutes together, and that his star quarterback felt good.

“No dizziness, no headaches, no vomiting,” Shanahan said. “He feels like he’s done well on the tests he’s taken thus far. . . . So, hopefully there’s no symptoms that happen over the next couple days.”

Backup quarterback Kirk Cousins, who spoke with Griffin on Monday morning at a mandatory rookie orientation meeting, said the starter did not appear to be suffering problems from the hit to the head that had sidelined him.

“He seemed fine, seemed in good spirits. He appeared to be doing well,” Cousins said.

Griffin was scheduled to see an independent neurologist Monday evening. If he passes tests administered by that physician, he would be evaluated on a treadmill and do other physical work Tuesday, Shanahan said.

Before he can receive clearance to play, Griffin must pass neurological tests administered both by team doctors and an independent neurosurgeon, and must demonstrate that he can exercise at game-level exertion without a recurrence of concussion symptoms, according to Thom Mayer, medical director of the NFL Players Association.

The neuropsychological evaluation typically includes elements that measure reaction time and shape recognition, Mayer said. Many NFL teams use the computerized ImPACT (Immediate Post-Concussion Assessment and Cognitive Testing) test, Mayer said. To pass, Griffin would have to achieve results comparable to his baseline results from previous testing. Shanahan was unsure whether the Redskins employ the computerized testing system.

According to the ImPACT Web site, the test measures “verbal and visual memory, processing speed and reaction time.” Reaction time is measured to a hundredth of a second. The test, which takes approximately 20 minutes, measures aspects of cognitive functioning that include attention span, working memory, sustained and selective attention time, non-verbal problem-solving and reaction time.

Shanahan expressed optimism that Griffin would be able to play Sunday. But the coach said it is possible for the quarterback to suffer a setback in coming days that could prevent him from playing.

That would leave Shanahan with a decision about whether to start Cousins, the rookie fourth-round draft pick, or 10th-year veteran Rex Grossman. Cousins took over for Griffin on Sunday and played 13 snaps, completing 5 of 9 passes for 111 yards and a touchdown, with two interceptions. Grossman has been inactive for all five Redskins games this season.

Shanahan wasn’t ready Monday to announce who would start in place of Griffin, but expressed confidence in Cousins despite the two late interceptions that halted Redskins comeback attempts.

“I think first of all, we’re going to go through the process with Robert,” Shanahan said. “Hopefully there’s no setback and he’s ready to go. I have a lot of confidence in both quarterbacks, Kirk and Rex. But Kirk has been No. 2 for a reason, because we feel he’s earned that right. We feel very good about him and where he’s at. But I also feel very good about Rex as well.”

Grossman and Cousins said the uncertainty of Griffin’s availability for Sunday would not cause them to prepare any differently this week. Their snap counts could increase if Griffin isn’t cleared before Wednesday’s practice, but they said they expected to go about the week the same way they always do.

“I can’t control the reps I get or when I go in,” Cousins said. “What I can control is my preparation on my own, in terms of film study and drawing plays and everything, every detail of how I approach my day, from the sleep I get to what I do at night when I go back to my apartment.”

Griffin suffered the concussion as he scrambled to his right on third and goal from the Atlanta 3-yard line. He tried to find an open receiver in the end zone, then elected to tuck the ball and try to run rather than throw it away. As Griffin tried to turn the corner, Atlanta linebacker Sean Weatherspoon made a clean tackle, but hit Griffin hard in the side of the head with his shoulder pad.

Griffin’s attempt to make a play rather than throw the ball away was an example of his ongoing acclimation to the NFL. Shanahan praised the quarterback’s competitive nature, but said Griffin needs to better protect himself. The coach hopes Griffin can learn from Sunday’s incident.

“Any time you get a hit like that in the National Football League, at least in my experience, when the quarterback gets a big hit like he received, they slide a bit sooner,” Shanahan said. “In plays that come, they kind of protect themselves a little bit more.”