Hypothetical: Zambrano goes 6 innings and throws 110 pitches. He's pinch hit for in the bottom of the 6th. Game becomes tied and ends up going 14 innings. That's 8 innings from the bullpen. Maddux gives up 10 runs in 1.1 innings. He obviously doesn't have anything decent and this game is already way out of hand. You can leave Maddux in, but why stretch him anymore than the 75 pitches he's already thrown? So, now you have to use the entire bullpen to finish up the last 7.2 innings of this game. Next game, Rusch fouls a pitch off his ankle in his first at bat and cannot continue in the game. The bullpen now has to work another 5 to 7 innings. Wouldn't it be nice if you weren't completely wearing out the bullpen in Maddux' meaningless blow out game? The bullpen might have been able to be sharp covering for Rusch. You have 4 starters, 7 bullpen guys and 1 long relief man for bullpen protection. Sure, my hypothetical is far fetched. But, it's not impossible. It's also not impossible to have back to back extra inning affairs. And it's not unreasonable to think that there might be a 1 1/2 hour rain delay after the 1st inning of an April game that would send your starter to the showers early, forcing you to use the bullpen for that entire game as well. There is room at the end of the bench for a spot starter/long relief guy, even if he isn't all that good. Rain happens, injuries happen and extra inning games happen. The extra arm is more important than the extra bat, IMO.