Who said anything about steroids?
Seriously though: there is only one witness who admits 1) she was really drunk at the time, 2) she was really high at the time, 3) she was really pantsless at the time, and 4) she really can't remember anything that happened at the time but also says she remembers Jon driving her car sometime, maybe at the time, who knows? Without Jon's history, no prosecutor would even file this case. As is, they're just hoping he agrees to a lengthy license suspension in exchange for dropping the charges.
None of which is to say that I believe that Jon is innocent; he probably isn't, but that doesn't change the fact that this is a particularly crappy misdemeanor case with little chance of getting a conviction.