Quarterback Dieter Brock of the Winnipeg Blue Bombers, two-time winner of the Schenley Award, emblematic of the Candian Football League's most valuable player, announced he will retire immediately because the club refused to let him out of his $1.1 million contract.

Brock said he would consider playing for the U.S. Football League's Washington Federals, which is coached by former Winnipeg coach Ray Jauch. However, Brock is still under contract to Winnipeg. He had offered to play for the 1983 season if Winnipeg would let him out of his five-year contract, which expires in 1986, and allow him to play in the NFL . . .

The Redskins signed four free agents following the college draft, General Manager Bobby Beathard said. They are Atlantic Coast Conference cornerbacks Dee Dee Hoggard (North Carolina State) and Darryl Smith (Virginia), running back Greg Jones (Alcorn State) and tight end Gerald Toney (The Citadel) . . .

The Los Angeles Raiders' top pick in the NFL draft underwent major back surgery to repair a ruptured disc just eight days before the draft and did not inform the team.

Don Mosebar, a 275-pound all-America offensive lineman from the University of Southern California, was the 26th overall draft pick and the Raiders' only first-round selection.

The Raiders were pleased with finding the lineman still available when their draft turn came. But when the news leaked out about the surgery, Raiders' owner Al Davis and other team officials were reportedly furious.

Mosebar had a 3 1/2-hour operation in Pasadena. Doctors removed more than half of his lowest disc . . .

The NFL Players Association said it tries to help rookies avoid being deceived by unscrupulous agents in contract negotiations.

NFLPA Executive Director Ed Garvey said the union is trying to help the rookies, even though they aren't yet union members . . .

Tennis: Vitas Gerulaitis scored 17 aces during his easy 6-7 (7-3), 6-4, 6-2 upset of No. 3 seed Guillermo Vilas in a quarterfinal match at the $300,000 World Championship Tennis finals in Dallas.

No. 2 seed John McEnroe defeated Tomas Smid, 6-1, 6-4, 6-3.