Twins general manager Terry Ryan said Capps irritated his rotator cuff while pitching the ninth inning on Monday against Baltimore. It was only Capps' second appearance after he missed 15 games with right shoulder inflammation.
Right-hander Nick Blackburn will be recalled from Triple-A Rochester to take Capps' place on the 25-man roster. Blackburn, who is 2-0 with an 0.60 ERA in two starts with Rochester since being sent there on July 4, will join the Twins on Wednesday.
Capps made two rehab appearances for Class A Advanced Fort Myers before being activated from the DL on Friday.
"There wasn't any urgency to rush back," Ryan said. "He was doing fine on the rehab assignment. Last night, he did something to irritate that thing."
Capps owns a 3.81 ERA in 29 appearances for Minnesota this season. The right-hander has successfully converted 14-of-15 save opportunities.