"out of left field" (Why "left"?)

[RonButters at AOL.COM]

In a message dated 2/28/01 10:39:01 AM, laurence.horn at YALE.EDU writes:

<< What makes us prefer "out of/in left field" is, I've
always assumed, the general association of leftness with the weird or
unconventional (due to properties of both handedness and politics).
 >>

I always thought that it was because the left-field fence was often placed
farther away from home plate than the right-field fence (because more long
balls are hit to left field than right). Hence "way out in left field" is as
far away as one can get from the center of the action.