Ross Ohlendorf struck out six hitters last night. So what does that mean?

Before last night's game, I wrote this: I'm already pretty convinced that his time remaining in the rotation is limited and a good start against the Astros won't change my mind, but I do suppose it'll be a start. Ohlendorf then went out and struck out six Astros over five solid innings and I'll admit it, I'm intrigued now. I'm a Pirate fan. I get intrigued by the most vaguely impressive things. So let's ask the question up front: Did Ross Ohlendorf look good last night because he was pitching against the Astros, or because he was actually pitching well? The first question is about his velocity. He just can't be that effective when his fastball sits in the very low 90s. In one of his last good starts from 2010, August 13th in Houston, his fastball averaged 93.3 mph and topped out at just over 95. Against Milwaukee in his first start back from the DL, his averaged 90.5 and topped out at 92.5. Last night, he averaged 90.7 and topped out at 93.4. So h...