In AAA you can get by fairly well with a 98 mile an hour heater, and below average secondary pitches. While I have not seen Homer pitch this year I think his walk total proves that his secondary pitches need work. I would think that because Homer Bailey would not be the number one pitching prospect in baseball if he couldn't locate that fastball.
I have a feeling that if Bailey were to be called up at this point he may get lit up after a trip or two through the lineup, once the hitters started sitting on the fastball. I could be wrong, but that's my .02