This is a break down of my staff from last post season (WS winner). I essentially had 6 starters, and a SUA that can go 140-150 innings a season. I tandemed my best SP with my SUA, my #2 with my #3, and my #4 with my # 5 (trying to go left/right as much as possible). I am one of the few that employes a closer when I have a pitcher good enough, and left him as my closer. My goal was to have my tandems go 8 (4 innings each) every 3rd game. I was actually a little inning heavy on the front part of the tadem
I actually carried 12, but as you can see 1 never saw an inning and 1 made 1 appearance over 15 ish games. So, yeah, you can get by with 10 if you have the right staff.