I think, at best, it'll end up around 8th or 9th. Wait until the dead period ends and a bit more coaches sign on every where for more shuffling. More than likely, a few players will end up leaving their commitments behind from the previous staff but Brohm will likely pickup equal or better ones...as he has already shown.
Given that Brohm will have an entire recruting season AND the new facility for next year, I think a top 6 class would be ideal next season. That would place Purdue behind OSU, UM, PSU, Whisky, and Nebraska. If Purdue can get to that point consistently under Brohm, it bodes well for the rebuild BUT will likely mean bumps along the road as those younger players play early.