When i read it, i was tryin' to come up with ways that it would lower: sacrifices, or ways to reach base sans PA (hit by pitch, or interference) and then get erased by double play, picked off, or caught stealing. But yeah, in context i think it was just to get a reasonable lower bound. Otherwise, i went lookin' back at Carlos Silva's 2005 9 walk season, but there wasn't more than a 4 game gap between walks there that i saw...