With Joe Washington's availability for Sunday's game against Buffalo still uncertain, Redskin quarterback Joe Theismann spent part of his day off yesterday throwing passes to Washington's backup, Nick Giaquinto, during a snow shower at Redskin Park.

Giaquinto, signed two weeks ago after being waived by Miami, played almost a half against Dallas last Sunday despite some unfamiliarity with the offense.

"Considering Nick has been with the team only a short while, he was pretty familiar with the offense Sunday," Theismann said. "But we still had to spend some time in the huddle talking over what he can do, and that can cause a problem when you only have 30 seconds to get off a play.

"We worked out last week on Tuesday. I'll do anything I can to help out a new player, so he can get familiar with what I do and I can get familiar with him. This offense depends so much on how we react to each other that you can't be strangers."

If Washington can't play against Buffalo, he will be replaced by fullback John Riggins. Giaquinto, however, will take over on passing downs; he was signed primarily because of his pass catching. Coach Joe Gibbs said he also would use fullback Otis Wonsley.

Defensive Coordinator Richie Petitbon said the nickel defense would benefit from cornerback Lemar Parrish's return. Parrish still is recovering from minor surgery. "Even if Lemar isn't 100 percent to start, we can use his experience in the nickel," Petitbon said . . . Linebacker Charlie Weaver (sore knee) has been added to the team's injury report . . . Gibbs on the play of his special teams against Dallas: "They were excellent. They played the best of our three units."