"The things I was allowed to experience, the people I was able to call friends, teammates, mentors, coaches and opponents, the travel, all of it, are far more than anything I ever thought possible in my lifetime," he wrote.
Schilling had surgery last June and had said he might come back in the middle of this season. He was not under contract for this season. He made no reference to his injury on his blog.
Schilling won a World Series with Arizona in 2001 and with Boston in 2004 and 2007.
In his first year in Boston in 2004, he helped the team win its first World Series in 86 years, pitching Game 2 of a sweep of the St. Louis Cardinals after a surgical procedure to suture a loose tendon in his right ankle and with blood seeping through his sock. The sock is now in the Baseball Hall of Fame.
He was drafted by the Red Sox in the second round of the 1986 draft, but was traded to the Baltimore Orioles before playing for the big league club. He pitched for the Orioles, Houston, Philadelphia and Arizona before being wooed to the Red Sox by general manager Theo Epstein.
Schilling, one of the sport's hard throwers, finishes his career with 3,116 strikeouts, 14th most in baseball history, a 216-146 record and a 3.46 ERA.
He was even better in the postseason, with an 11-2 record, the best of any pitcher with at least 10 decisions, and 2.23 ERA in 19 career starts.
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