Sounds to me like he got drug tested while in the hospital getting surgery or something because look at his twitter timeline.
On sep 9 at 1:34 pm:
For those of you all that know me, you'll know better. For those that don't have faith. I should have never got sick
https://twitter.com/PrinceSpearmon/status/509409601662767104
Then at 1:43 pm he sent this, which looks like he meant to set it privately to someone:
"Man ill call you and tell you how they got me though."
https://twitter.com/PrinceSpearmon/status/509411689369202688
So chances are he was on meds because of the surgery and when they tested him something he'd taken was banned.
The athletes like Wallace can't win. The ones that have the money to get the stuff that's actually making them stronger and faster and that can't get detected are the ones who are really winning.