NEW YORK -- Boston Red Sox left-hander Kent Mercker declined a $1.75 million player option and filed for free agency Monday.
Mercker, traded from St. Louis to Boston on Aug. 24, was 6-5 with a 5.12 ERA in 18 starts and seven relief appearances for the Cardinals, then went 2-0 with a 3.51 ERA in five starts for Boston.
He gave up two runs in 1 2-3 innings against Cleveland in the first round of the playoffs and four runs and 12 hits in 7 2-3 innings against the New York Yankees in the AL Championship Series.
Also filing Monday were Texas right-hander Mike Morgan and St. Louis right-hander Heathcliff Slocumb.
Detroit, which acquired outfielder Juan Gonzalez from Texas last week, got a formality out of the way by exercising his $7.5 million option. Gonzalez is eligible for free agency after next season.
A total of 108 players has filed for free agency, and 25 more are potentially eligible to file by Thursday's deadline.