This'll be a great fight that'll go all five rounds. BJ could win if he outboxes Diego, but with Diego's aggressive ways, that's going to be even tougher than it would've been with Sherk or Kenny.
Plus, Diego's never been knocked out, and I'm not even sure if I've ever seen him rocked, even. (If I'm wrong please correct me.) But either way this will be the real test for BJ. If he wins this, there's no one at LW that can stop him, save for maybe a wrestler like Frankie Edgar, but I would doubt it.