The Minnesota Twins have signed pitcher Rich Harden to a minor league contract with an invitation to spring training.

Harden, 31, had surgery to repair his right rotator cuff on Jan. 31 and missed the entire 2012 season with a shoulder strain.

He made 15 starts for Oakland in 2011, going 4-4 with a 5.12 earned run average.

The injury-plagued hurler can be quite effective when healthy. He boasts the third-best strikeouts-per-nine innings ratio in the majors since 2003.

Harden is 59-38 with a 3.76 ERA in 170 career games, all but 10 as a starter, with the Athletics, Cubs and Rangers.

The Twins also announced pitcher Scott Diamond underwent a scope Tuesday to remove a bone chip from his left elbow. The team is confident he'll be ready for spring training.