Mikey could UD him but it won't be easy, Beltran is one of those vets with sneaky power that will hurt you if he catches you slipping, like Collazo did Thurman.
Ray's got more juice in him than a supermarket, but Mikey's still too good for him. When a guy pops positive, there's two possible routes: you either straighten up and fly right, or you tweak your recipe. Given that Beltran had a sub 50% knockout rate prior to the test and has knocked out everyone since he tested positive (usually damn near leaving them in the morgue), it looks like he took the second option lol