Valid points by Boog - it really doesn't matter it depends on how you want to manage the staff. You could have 8 and be successful but I wouldn't want to manage that. Everytime I have less than 11 I run into fatigue issues. Even if you manage them well you will run into a couple 15-13 games back to back that burn up your staff or consecutive extra inning games. I usually have room for 11 as I only need 14 hitters, 8 position and a backup C, 1B, 2B, 3B, SS and OF. A couple of times I've gone 15/10 But I've never tried 9 for more than a couple weeks. Too much work.