Duh, of course it was him! Today he admits that yeah, he smoked weed and you know what? Being high is fucking awesome you should try it some time, doodz! In a statement to the AP, Phelps admits
I engaged in behavior which was regrettable and demonstrated bad judgment...I'm 23 years old and despite the successes I've had in the pool, I acted in a youthful and inappropriate way, not in a manner people have come to expect from me. For this, I am sorry. I promise my fans and the public it will not happen again.
The "it" that will not happen again, we take it, refers to being caught in the act. Because the hits keep coming and Phelps is most definitely getting toasted next Friday. After all, he ain't got no job and he ain't got shit to do.