Pittsburgh center fielder Andy Van Slyke Saturday signed a three-year contract extension reportedly worth $12.6 million, which would make him the Pirates' highest paid player.

The extension takes effect next year and runs through 1994, but neither the Pirates nor Van Slyke provided any other details.According to the Pittsburgh Press, however, the pact includes a $750, 000 signing bonus for this year and provides for salaries of $4 million in 1992, $4.6 million in 1993 and $3.3 million in 1994.

Van Slyke currently is in the final year of a three-year, $5.5 million contract that, at the time of his signing, made him the Pirates' highest paid player.

Over the winter, pitcher Zane Smith signed a four-year contract valued at $10.6 million, and Cy Young Award winner Doug Drabek won a $3. 3 million contract in arbitration.

Right fielder Bobby Bonilla recently rejected a $16 million, four-year deal and is eligible to become a free agent at the end of the season.

In contrast to the Bonilla negotiations, Van Slyke's contract was settled without fanfare.

"We wanted to sign Andy all along," said General Manager Larry Doughty. "We didn't do this because of the Bonilla situation.

"The main thing was that it was done in good faith. Andy has a competent agent."

The latter remark might be read as a criticism of Bonilla's agent, Dennis Gilbert.

The signing of Van Slyke should be reassurance to other Pirates that the team will make a serious effort to keep players from jumping to larger markets.

"I said when Andy signed his first contract with us that he was the cornerstone upon which we could build, and that has not changed today," said President Carl Barger.

Van Slyke came to Pittsburgh in April 1987 with catcher Mike LaValliere and pitcher Mike Dunne from the St. Louis Cardinals in return for catcher Tony Pena.