BRISTOL, Conn. -- Mark McGwire, the former single-season home run king, told ESPN that he is "worn out" and will retire from baseball.
McGwire strongly hinted of retiring several times this year, when he batted just .187 with 29 home runs as he was slowed by a bum right knee.
ESPN anchor Rich Eisen said he received a telephone call from McGwire on Sunday night and the slugger said that he was "extremely happy with the decision."
McGwire had agreed to a $30 million, two-year contract extension in spring training but never signed the deal.
"After considerable discussion with those closest to me, I have decided not to sign the extension, as I am unable to perform at a level equal to the salary the organization would be paying me," McGwire said in a statement to ESPN. "I believe I owe it to the Cardinals and the fans of St. Louis to step aside, so a talented free agent can be brought in as the final piece of what I expect can be a World Championship-caliber team."
McGwire captured the nation's imagination in 1998 while hitting 70 homers to break Roger Maris' 37-year-old record. It was a short-lived mark as Barry Bonds hit 73 homers this season.
McGwire has 583 career home runs, fifth on the career list, and finished his career 17 shy of becoming the fourth player to hit 600 homers.
McGwire, who began his career with Oakland in 1986, won the World Series with the A's in 1989 and reached the postseason six times.
"For years I have said my motivation for playing wasn't for fame and fortune, but rather the love of competing," McGwire said in the statement. "Baseball is a team sport and I have been lucky enough to contribute to the success of some great teams."
He labored through the 2000 season with a bad right knee, missing virtually all of the second half. He had surgery to correct patella tendinitis but again struggled with the knee this season.