You can see exactly what happened on the vid. He's lined up way offsides, almost a full yard, not even close. Right before the snap he looks over to the official and then moves back like a foot. But he moved back so little, he was still clearly offsides.
And then a half second later, the ball is snapped. If they didn't call him for offsides, they could have called him for illegal motion.
Total bonehead move. Probably explains why he's played so little. And worse, it sounds to me like he lied to Mike about what happened, or at least didn't tell the whole truth. I would get Washington ready and sit this guy for a long while.