1-Jay knew he looked horrible many months ago and would no way be acceptable for a Mr. O. His body was horrid beyond description.
2-Dex was the only other option, he was next in line: he had been contender for so many years with Jay and Ronnie, he had "paid his dues", couldnt let a new guy like Heath or Wolf win. Even tho heath > dex
3-His body may get screwed at any time now and pull a Cutler, or get injured.
4-Muscletech endorsee also
they werent gonna lose any money from jay not winning