Baseball and number crunching

I kindof have a thing for numbers and simulations. I enjoyed the Moneyball book about stats Billy Beane looks at when trying to get the most bang-for-buck out of the Oakland A's low budget - doing so by identifying overlooked characteristics of players games that contribute to wins (a picky batter who walks alot), and by also identifying characteristics that other teams overpay for (hot relief pitchers - it's often just a statistical run of good luck).

Here's a story about a computer simulation that helps investigate questions such as:
- does a sacrifice bunt make sense?
- should your best slugger always hit 4th?
- should a team attempt to steal bases more or less?
- Does the intentional walk help or hurt your chance of winning?

(you can find the answers in the story)

I haven't watched a baseball game in years, but it's interesting that the statistical questions about the game are still engaging.

Here's the one I want to know.
Does it make sense to change pitchers to bring in a lefty pitcher to face a single lefty batter?

When I was younger it seemed kindof strange to me to use up your bullpen warming up and bringing in a pitcher to face a single batter. Or over the long haul does alot of bullpen activity just wear out the staff?