Bronx, NY -- (Sports Network) - New York Yankees right-hander Mike Mussina, as expected, retired on Thursday after 18 seasons in the major leagues.

Reports circulated on Wednesday that Mussina had decided to call it quits after the first 20-win campaign of his illustrious career. He finished the 2008 season with a record of 20-9 and a 3.37 earned run average in 34 starts for the Yankees, and was awarded his seventh Gold Glove.

At age 39, Mussina became the oldest pitcher in baseball history to record 20 wins in a season for the first time in his career. Jamie Moyer held the previous mark with his first 20-win season in 2001 at age 38.

Mussina's 2,813 career strikeouts ranks sixth among active pitchers and 19th on the all-time list. The first-round pick of the Orioles in 1990 completed his career with a 270-153 record and a 3.68 ERA. His .638 career winning percentage is sixth-best all-time among pitchers who made at least 500 career starts, and his 270 victories ties him with Burleigh Grimes for 32nd place on the all-time list.

Mussina has pitched his whole career in the American League East -- the last eight seasons with the Yankees and the first 10 of his career with the Baltimore Orioles. Signed as a free agent by the Yankees prior to the 2001 season, Mussina compiled a record of 123-72 with a 3.88 ERA in eight seasons with New York. No American League pitcher has recorded more wins during that time period, and Mussina's 1,278 strikeouts while with the Yankees ranks sixth on the club's all-time list.

"It was a great pleasure playing against - and even more so - with Mike Mussina since I entered the league in 1995," said Yankees shortstop Derek Jeter. "He was a true professional both on and off the field. Moose's accomplishments in the game over the last 18 years represent a Hall of Fame player."

He won 15 games in a season 11 times during his career, and six times placed in the top five for Cy Young Award voting, though he never won it. Mussina ostensibly came to New York with the hope of winning a World Series in mind, joining the club after the last of its three straight titles from 1998-2000, but he never did get a ring.

The Yankees made two World Series appearances during his tenure, but both were losses -- in 2001 to Arizona and in 2003 to Florida. Mussina finished his career with a 7-8 playoff record and a 3.42 postseason ERA.

Mussina, a native of Montoursville, Pennsylvania, was known for his control, and walked only 785 batters in 3,562 2/3 career innings, a ratio of 1.98 walks per nine innings pitched. According to the Elias Sports Bureau, Mussina is one of only three pitchers in MLB history to throw at least 3,000 innings and hold opponents to fewer than two walks per nine innings pitched, joining Jack Quinn and Cy Young.