Suspended Boston Red Sox pitcher Dennis (Oil Can) Boyd pleaded guilty yesterday to a 1983 speeding charge and said he wants to rejoin the team following a week of hospitalization.

Boyd, on temporary leave from the University of Massachusetts Medical Center, where he was undergoing drug and medical tests, was arrested on an outstanding traffic warrant Wednesday night after his wife was stopped for speeding.

Appearing in Wrentham (Mass.) District Court, Boyd paid a $25 fine for the June 11, 1983, violation, and later was discharged from the hospital.

Red Sox General Manager Lou Gorman, with the team in Anaheim, Calif., said Boyd probably would not rejoin the club before it returns to Boston Aug. 1. The team denied trade rumors surrounding Boyd.

Boyd entered the courthouse parking lot in a silver Mercedes-Benz, accompanied by his wife, Karen; his agent, George Kalafatis, and his attorney. He admitted driving 87 mph in a 55 mph zone.

"They were complaining about my not getting to the ballpark early, man," Boyd said of the Red Sox. "All I was trying to do was get to the ballpark early." . . .

The Baltimore Orioles are ready to switch flagship radio stations next season, moving from WFBR in Baltimore to WCBM. Tom Marr, No. 2 man in the booth to Jon Miller, supposedly will be replaced by veteran Chuck Thompson. WTOP in the District will continue coverage.