MINNEAPOLIS — The Twins and right-hander P.J. Walters have agreed to terms on a minor league contract, and Walters has received an invitation to spring training, the team announced Monday.

Walters signed with the Twins last December as a six-year minor league free agent, one of 35 pitchers invited to major league camp as the Twins tried to bolster a feeble bullpen. But because of injuries and ineffectiveness in the rotation, Walters was recalled as a starter and went 2-1 with a 2.96 earned-run average in his first four starts.

Shoulder problems, however, sidelined Walters in mid-June and he didn’t pitch again until Sept. 5, going 0-3 with a 6.12 ERA. He was outrighted off the 40-man roster last week.

He will turn 28 on March 12.

Right-hander Nick Blackburn, demoted to Class AAA Rochester in August and soon after released from the 40-man, had surgery to remove a bone chip from his elbow last week. The Twins expect him to be ready for spring training.