Tarnok (shoulder) dealt with a blister issue during his rehab start with Triple-A Las Vegas on Wednesday, Martin Gallegos of MLB.com reports.
Tarnok gave up two runs in four innings while getting his pitch count up to 61 in the outing but developed a blister. He's considered day-to-day, so it's possible he could be ready in time for his next rehab start. Tarnok has been on the injured list all season with a right shoulder strain.