I'm suggesting that the NCAA went to UF on before Saturday's game and said your boy tested positive for steroids. I am also suggesting that it is reasonable that either the NCAA representative, UF compliance officer, HC, OC or QC (or any combination of those) went to Grier before the game to tell him he tested positive for steroids. I make that assumption because there is no player liaison as there is in the NFL.
Now, we can make either assume that Mizaru, Kikazaru and Iwazaru are on UF's coaching staff and they did not take the next logical step of asking Grier if he did, in fact, take steroids. Acting as the three wise monkeys is likely the best case for the team in this scenario. However, we can make the conclusion that someone on UF staff knew, Grier knew and the NCAA knew--but they also knew they had the safe-harbor of the time it apparently took to test the Sample B. So he could play this one game.
But if he wasn't eligible to play. Doesn't UF forfeit this win.