Theme restrictions aside, I agree with Italyprof - I know, a rarity (lol). My predilection for the three-man rotation pre-dates the Deadball Era preference, however; looking at the playoffs a 4th starter may not get used in the 1st round (if you're lucky); and in subsequent rounds your ace only gets two starts - one of which is most likely not Game 7. Now, you can drop your 4th starter from the rotation in the playoffs and move him to the bullpen, but he's most likely not a Long A (I hope your pen has better stats than your 4th starter), and you're leaving a lot of money on the table by not using him. You're basically paying $5-$8 million for a Long B in the playoffs, and probably not your first choice at Long B.