Manager Ron Gardenhire said Wednesday that Perkins will have dye injected into his shoulder before the exam in hopes of determining more precisely what is wrong. His first MRI exam on Tuesday came back inconclusive.
Perkins, who was 6-7 with a 5.89 ERA, was placed on the disabled list retroactive to Aug. 9.
He was replaced on the roster by right-hander Jeff Manship, who was 4-2 with a 3.22 ERA in eight starts at Triple-A Rochester. Perkins had earlier lost his starting job when the Twis picked up Carl Pavano.