I watched his last two starts. He looks alright, but loses control at times. What worries me most about young pitchers is the walks and lack of control, and O'Connor suffers from both of these. His ratios are very good right now, but I would not bet on them staying that way. In addition, the offense behind him is not the best.
If there are no clear better options I would take a chance on him, but I would rather have a veteran that would put up similar numbers. I would guess 12W, 4.50 ERA, 1.35 WHIP and 120K