Former pitcher Bob Welch dead at 57

March 1, 1987: This file photo provided by the Los Angeles Dodgers shows pitcher Bob Welch. Welch, a former All-Star pitcher with the Los Angeles Dodgers and the Oakland As, has died. The two-time All-Star and Cy Young award winner was found dead at his home in Seal Beach, Calif. He was 57. (AP/Los Angeles Dodgers/File)

OAKLAND, Calif. – Bob Welch, the 1990 AL Cy Young Award winner of the Oakland Athletics and the last major leaguer to win at least 25 games in a season, has died. He was 57.

He died Monday night in Seal Beach, California, of unknown causes, the team said Tuesday.

"He was a legendary pitcher who enjoyed many of his best seasons with the Oakland A's," A's President Michael Crowley said in a statement. "He will always be a significant part of our franchise's history."

Welch was a prominent member of the Oakland teams that won three straight AL championships from 1988-90, including the 1989 club that swept the San Francisco Giants in the earthquake-interrupted World Series. He won the Cy Young Award after going 27-6 with a 2.95 ERA.

Welch finished 211-146 with 3.47 ERA in 17 seasons with the Los Angeles Dodgers (1978-87) and Athletics (1988-94). He also was the pitching coach for the Arizona Diamondbacks when they won the 2001 World Series and has served as a special instructor for the A's in recent years.

"This is a sad day for the entire A's organization," general manager Billy Beane said. "Those of us who knew Bob as a teammate and a friend will miss him greatly."

A's left-hander Sean Doolittle wrote on Twitter: "Devastated to learn of Bob Welch's passing. The A's organization lost not only one of its best pitchers, but one of its best people."