Tarnok (hip) covered 1.2 innings and gave up four earned runs on one hit and two walks in his latest rehab appearance for Triple-A Las Vegas on Saturday.
Tarnok has worked as a starter for most of his minor-league career and in his brief time in the big leagues, but Oakland may be preparing him for a relief role upon his return from the 60-day injured list. The 25-year-old righty -- who has been on the shelf all season while recovering from August surgery on his right hip -- has been deployed out of Las Vegas' bullpen in each of his last four rehab appearances. He hasn't recorded more than six outs in any of those appearances and owns a 13.50 ERA and 1.67 WHIP over his five total rehab outings, so Tarnok looks like he'll need more time to iron out the kinks during his rehab assignment before he becomes a realistic option for the Oakland pitching staff in any capacity.