Athletics manager Mark Kotsay said that Blackburn came away from his latest rehab start for Triple-A Las Vegas on Sunday with a blister on his middle finger, and the right-hander's next appearance is in doubt, Martin Gallegos of MLB.com reports
Blackburn struggled in the outing with four runs allowed on six hits and two walks over 2.2 innings, and the blister likely played a part in it. Considering that Blackburn was already rehabbing a middle finger avulsion before developing the blister, he may require some time off for the blister to heal before he resumes his rehab assignment.