Richard Williams, running back drafted in the second round from Memphis State, and Alvin Garrett, resident Smurf wide receiver, are having problems at the Washington Redskins training camp.

Williams is a sleek 6-foot, 205-pound back, who has looked both fluid and strong during practices, but has played poorly in the two scrimmages against the Baltimore Colts, gaining a total of 17 yards in 10 carries. Meanwhile, Marcus Gilbert, a ninth-round pick from Texas Christian, seemingly has moved ahead of Williams in the eyes of Redskins coaches.

"Richard needs to relax. So far, he's been very tentative," said Don Breaux, running backs coach.

"I've let personal problems from back home get to me. I didn't talk to anybody about it and it hurt the way I was playing," Williams said. "But it's all behind me now."

Garrett's problem is simple: he is out of shape. Right now, Garrett weighs 196 pounds, which is a lot to pack on to a 5-7 body.

Coach Joe Gibbs is not pleased. "Alvin is one of the guys I'm concerned about," Gibbs said. "We'll have to see how long he can play in games in the preseason and we'll have to run him more. I'd like to see him drop another seven or eight pounds."

"I weighed 200 pounds in the Super Bowl, but I was strong then. Right now I don't have my wind," said Garrett, who caught just one pass during the regular season last year, then caught 15 in the playoffs, five for touchdowns. "I would like to lose three or four pounds a week now. I'd like to play at 180-185, which is about what I played at last year."

Gibbs said Darrell Green, top draft pick from Texas A&I, likely will start at cornerback in the preseason opener Saturday night in Atlanta. "That's what I need most, game experience. I can't get anything but better," said Green, who will also return punts in the game . . .

The Redskins trimmed the roster to 85 today, cutting rookie punter Gene Muriaty (North Carolina) and rookie punter/kicker Danny Paro (Denison) . . . Defensive end Dexter Manley, who cut his hair in a Mohawk, has been abbreviating his autograph to "Mr. D." . . .

Second-year tight end Mike Williams, who was a starter at the beginning of last year and who tore knee ligaments against the New York Giants in the seventh game of the season, has been slow in his recovery. Though he is running and lifting weights, Williams still is not working out with the team. "The problem is he's had swelling fluids and we can't jeopardize his future," said Gibbs. Williams is on the physically unable to perform list.