I remember Eric Byrnes used to use "Your Love" as well a few years ago. Don't know if he still has that one now.
There are a lot of ways you could go here, but I would go "When Everything Falls" by Haste the Day. Great song, especially the first 40 seconds or so which is what would be playing while you go up to bat.
We did this one year in high school baseball and one of my friends used "The Good, The Bad, and The Ugly". You know, the one where there's whistling involved. It was hysterical. The pitcher would have to call time and gather himself half the time because he was laughing so hard.