Redskins Coach Mike Shanahan said he knew Robert Griffin III was injured as soon as he came to the sideline Sunday.When Robert came off the field and I looked at his eyes, I knew something was wrong, Shanahan said. I said, Hey, go see the doctors. He said Im okay. I said, No, youre not okay.Twenty-four hours later, though, the quarterbacks condition has improved significantly according to Shanahan, speaking during his Monday afternoon press conference.Hes feeling good, the coach said. No dizziness, no vomiting. He feels like hes done well on the tests that hes taken so far.So whats next for Griffin and the Redskins? Several more tests before the rookie's status for Sundays game against the Vikings can be determined.Today is basically rest and testing, Shanahan said. Then tomorrow, if he passes the tests, hell get a chance to get some cardio work, get a little workout in on the treadmill, then if there are no symptoms like headaches, dizziness, nausea, things along those lines, then hell be able to practice on Wednesday as long as theres no contact.But if Griffin suffers a setback in the coming days, its unlikely hell play against Minnesota, Shanahan said. If that happens, the coach hinted that Kirk Cousins, another rookie, would be Griffin's replacement.We should find out in the next few days exactly what happens," Shanahan said. "Right now, it looks good. Not sure if it stays that way.Shanahan, however, is more certain of this: Griffin will likely do more to avoid the punishing blow delivered to him by Atlantas Sean Weatherspoon next time he's in position to slide.Its my experience when that quarterback gets that first hit like he received, they slide a little bit sooner, Shanahan said. They protect themselves a little bit more.Griffin is not permitted to speak to reporters until his has been cleared by doctors. His normal media availability is Wednesday afternoon.