He was scheduled to fight in mexico yesterday but the American boxing commision was trying to stop it from happening. Mexico does not require pre-fight blood tests and apparently they were going to let Tommy fight. I can't find any news about whether or not they let him fight or stopped him from fighting.
Edit: Nevermind. I guess they let him fight and he won by 3rd round KO ESPN - Chavez Jr. prevails by TKO in Mexico; Morrison wins, too - Boxing