http://247sports.com/Bolt/Heisman-Trophy-odds-Vegas-pegs-Derrick-Henry-as-huge-favorite-41355402
Henry's 2/5 odds of winning the stiffarm trophy give him an implied probability of 71 percent to become the second Alabama player to bring this particular piece of hardware back to Tuscaloosa. If you're trying to construct a scenario in which someone other than Henry wins, it likely involves the Crimson Tide losing Auburn and missing out on the SEC Championship game thanks to an Ole Miss win over Mississippi State, plus a pair of strong performances from Watson against Carolinas South and North. The latter seems far more likely to happen than the former, and that probably won't be enough on its own.