I wouldn't get too excited about anyone pitching for Baltimore. They have the 1st, 2nd, 4th and 8th best offenses (based on runs scored per game)in the MLB in their division so no matter how good the pitcher is they are going to struggle to put up good ratios with Baltimore playing so many games against those 4 teams. Meanwhile Baltimore is ranked 14th so wins against those teams won't be easy either. Let me fire one more stat at you so you can see how big a difference it is. Those 4 teams score 5.36 runs/game, the rest of the league scores 4.51 runs/game. That is a 19% difference. 19% is the difference between a 3.5 ERA and a 4.17 ERA so even a relatively good pitcher, on average, is going to be a poor one against those 4 teams.
One last thing before I stop rambling. Baltimore's opponents in August and September (key for a late July callup of course)...
Bos, Det, Tor, Oak, LAA, TB, CWS, MIN, CLE, NYY, TEX, BOS, NYY, TB, BOS, TOR, CLE, TB
That September especially is BRUTAL. I just took Tillman off my watch list.