by Ken Rosenthal

Mussina made the decision official on Thursday.

The Yankees, who are aggressively pursuing free-agent starting pitchers, were not expecting Mussina to return.

"I have not talked to him lately," Yankees manager Joe Girardi said Wednesday evening at a Manhattan charity event to benefit his Catch 25 Foundation and Alzheimer's research. "He had led me to believe that that's what was going to happen at the end of the year. I wasn't quite sure in a sense that I believed him because sometimes when you get away from it you really miss it."

Mussina, who turns 40 on Dec. 8, is coming off the first 20-win season of his 18-year career. He is selling his home in Bedford, N.Y., according to one source, and planning to spend more time with his family in Montoursville, Pa.

"I don't have any regrets. This is the right time," Mussina said on a conference call.

"I don't think there was ever a point where I looked around and said, 'You know what, I'm going to change my mind,"' he said. "It was like the last year of high school. You know it's going to end and you enjoy the ride."

Mussina held off his announcement until the completion of baseball's award cycle. He recently won his seventh Gold Glove, tied for sixth in the American League Cy Young award voting and even received one eighth-place vote for Most Valuable Player.

A first-round pick of the Orioles in 1990, he finishes his career with a 270-153 record and 3.68 ERA.

His victory total falls short of the unofficial Hall of Fame standard of 300 wins, but his candidacy for the Hall will be enhanced by the fact that he pitched in the Steroid Era and spent his entire career in the offensively oriented AL East.

Only 20 other pitchers in major-league history have finished 100 or more games over .500. Sixteen are in the Hall of Fame, and the other four — Roger Clemens, Pedro Martinez, Greg Maddux and Tom Glavine — are not yet eligible.

Only five pitchers in history have as many victories as Mussina (270) with a higher winning percentage (.638) — Lefty Grove, Christy Mathewson, Clemens, Randy Johnson and Grover Cleveland Alexander.

Mussina's 2,813 career strikeouts rank sixth among active pitchers and 19th all-time.

The Associated Press contributed to this report.