Al Davis, managing general partner of the Los Angeles Raiders, testified yesterday in Los Angeles he believed his club would have averaged between 80,000 and 85,000 fans per game had the team been allowed by the National Football League to move from Oakland in 1980.

Davis made his remarks in the damage phase of the antitrust suit that the team and the Los Angeles Coliseum Commission won against the NFL last May. The plaintiffs seek $23.5 million in damages.

The Raiders did not begin operations in Los Angeles until July of last year, several months after clubs usually begin selling tickets.

In the strike-shortened 1982 season, an average of 61,000 tickets were sold for Raiders home games . . .

The Washington Federals re-signed and activated rookie quarterback Chris Garrity. Garrity, who graduated from William and Mary last spring, will serve as backup to starting quarterback Kim McQuilken. Quarterback Mike Hohensee, who started and suffered a fractured sternum in last week's game at Los Angeles, has been put on the deactivated list along with running back Craig James (compression fracture of the upper dorsal spine) and wide receiver and kick returner Reggie Smith (dislocated foot). James and Smith also were injured against Los Angeles.

Wide receiver Jeff Kinney, defensive back Jeff Postell and running back Mark Sanford were all activated for Sunday's game at Boston, against the Breakers.

The Federals acquired guard Mike Wilson from the Arizona Wranglers for future considerations. Wilson spent the last three years with Edmonton in the Canadian Football League.

Federals Coach Ray Jauch said he expects to sign quarterback Joe Gilliam on Monday . . .

The Saskatchewan Roughriders of the CFL announced they have signed quarterback Homer Jordan of Clemson. No terms were announced.