Tarnok (shoulder) fired four scoreless innings in Triple-A Las Vegas' loss to Oklahoma City on Wednesday, allowing three hits while recording two strikeouts.
Tarnok has gotten more impressive with each rehab appearance, and Wednesday's outing saw him work up to 53 pitches. The promising right-hander would likely need at least one more start on the farm before being built up enough to be activated with an eye on joining the big-league rotation, but the fact he's already tossed 6.2 scoreless frames in the hitter-friendly Pacific Coast League supports the notion he'll have the ability to offer a boost to Oakland's starting pitching arsenal.