Dave Righetti of the New York Yankees became the first free agent of 1987-88 when he filed at 12:06 a.m. yesterday, one of 12 players who filed on the first permissible day (for others, see For The Record).

"The surest way of establishing in an emphatic way that David was interested in testing the free-agent market was to file six minutes after he was permitted to," Bill Goodstein, the left-handed relief ace's attorney, said. "I don't think there will be a repeat of 1985 and 1986." Goodstein was referring to the clubs' refusal to sign free agents. That led to two collusion grievances, one already won by the players.

"I think there will be a pursuit of selected free agents. I had conversations with teams that said they lost 41 games by one run after the seventh inning. They think someone like Dave can make the difference between 70 wins and 90 wins."

Righetti, 8-6 with 31 saves in 1987 after his record 46 saves in '86, earned $800,000 in the final season of a five-year, $2,925,000 million contract. Even though he is a free agent, he may not discuss contract terms with teams other than the Yankees until Nov. 9. By Dec. 7, the Yankees must offer him salary arbitration or lose the right to negotiate with him until May 1. If the Yankees do make an arbitration offer, they must sign him by Jan. 8 or lose him until May 1 . . .

Syd Thrift signed a two-year contract to continue as the Pittsburgh Pirates' general manager, just three days after pulling off a front office power play that led to the resignation of Malcolm (Mac) Prine as club president.

The new contract reportedly boosts Thrift's salary by $75,000 a year to $200,000 annually and gives him the final say on all baseball-related decisions.

And he made one yesterday, hiring former Cincinnati Reds director of scouting Larry Doughty to assist him in player acquisition and contract negotiations. Doughty quit the Reds last month after five years, citing interference from Marge Schott, the team president.

Thrift, 58, was a surprise choice when he was hired away from his Northern Virginia real estate firm two years ago.