I reckon he did it for some reasons; 1) Haymon told him to, the new TV deal wasn't ready at the time of the defence so he told him to vacate instead. 2) He said in an interview it gives him the opportunity to become a two weight world champion. 3) He also said in the interview that he was having family problems and he wasn't in the right place to defend his title. 4) Haymon wouldn't have wanted to work with a Roc nation maybe?