Blackburn threw three pitches to David Murphy and made three pickoff attempts at first base before he was visited at the mound by the Twins' training staff. After meeting with team trainers, Blackburn walked off the field and was replaced by left-hander Brian Duensing.
Blackburn wasn't around to speak to reporters after the Twins' 6-2 loss, as he was getting an MRI exam taken on his right shoulder.
A Major League source, however, said Blackburn's MRI exam showed no significant damage to his right shoulder. Twins general manager Terry Ryan is expected to give an official update Sunday morning.
But it was welcome news for the Twins that the injury wasn't related to Blackburn's right forearm, as he had surgery to stabilize an entrapped nerve in his forearm during the offseason.
Blackburn pitched well before exiting the game, allowing two runs on seven hits and a walk. He also struck out three and gave up a solo homer to Josh Hamilton in the third.
Despite entering the game with a 2-1 count to Murphy, Duensing struck out Murphy and was able to get Mike Napoli to fly out to right field to end the inning.