I don't think he used steroids to get bigger because his size increase over 10 years isn't that absurd. If you had a dietitian, chef, personal trainer, and your body was your job (not something you worked on outside of your 9-5), you could theoretically make the same gains naturally.
I believe that he is definitely abusing some kind of drug, though. I just don't believe that the goal of the drug is to build muscle.
The average Joe Schmoe could make those gains in a year. But we all know he wouldnít be taking enhancements just to pack on muscle.
I would not be surprised if he was messing with something while in Miami, the hotbed for athletes using PEDís. When he lost significant weight one offseason, thatís a pretty big red flag for someone who was clearly the best player in the game and dominating. To drastically change your body like that is questionable.
Maybe he was/is on something, maybe not. Or maybe they all are. Mariano Rivera is about the only athlete of this millinium that would absolutely shock me if we found out he used PEDís.