A jury of six was seated yesterday but Danny Ainge declared that no matter the outcome of the Toronto Blue Jays-Boston Celtics tug o' war in Manhattan federal court, "I'm through with baseball."

The sub-.200-batting third baseman from Brigham Young U., drafted by the NBA champions who seek to extricate him from a three-year Blue Jay contract (signed in September 1980) that denies him basketball, declared outside court: "Toronto feels that if they win the case, I'll sit home during the winter and come back for spring training, but . . . I don't plan on returning, no matter what . . ."

And if Ainge's claim of an individual's right to change jobs -- indeed, that Toronto President Peter Bavasi gave him oral permission to quit if he became disenchanted -- is denied?

"What would I do?" Ainge said. "I have a business in Utah and I'm pretty good at golf. Maybe I'll go on the pro golf tour. I've also had an offer to be the assistant basketball coach at Brigham Young. I have a lot of alternatives."

And what say you, Celtic Coach Bill Fitch? "Hope he's ready to go when our camp opens. I'm not too excited, though. Remember, we won the world championship without him last year."