Griffin has been out of action following knee surgery in the off-season after initially damaging his ACL in a playoff defeat to the Seattle Seahawks last season.
"He's ready to go. Full speed ahead," Shanahan told reporters. "If we didn't feel that Robert was full-go, he wouldn't be playing in this game.
"He's gotten a lot of great reps in practice, no setbacks, no swelling. I feel very good with where he's at."
Washington face the Eagles next Monday at FedExField.