Quarterback Rex Grossman has been hospitalized with pneumonia, head coach Mike Shanahan said.
Grossman was diagnosed with the illness during the weekend.
He traveled with the Redskins to Charlotte, N.C., for Sunday's game against the Carolina Panthers. He participated in warm-ups but he did not come out with the team for the game, instead staying inside the locker room.
Fortunately, Grossman was not needed. John Beck was named the starting quarterback last week so Grossman was in a backup role.
Shanahan said the team wanted Grossman to stay in the hospital through Tuesday.
"Hopefully we'll have him back by Wednesday or Thursday," Shanahan said. "With pneumonia and the type of temperature that he had, [Redskins team physician] Dr. [Tony] Casolaro felt that it was in his best interests to stay in the hospital for obvious reasons. Hopefully he keeps on getting better."
If Beck had suffered an injury in the Panthers game, then Grossman would have tried to play in the game, Shanahan said.
The Redskins have no third quarterback on the roster. It has been suggested that wide receiver Terrence Austin, a high school quarterback, would have been a candidate to play quarterback if Beck were sidelined with injury.