They don't have to have evidence that he hit her. Assault isn't the same as battery. No touching is necessary to commit the offense.
The court case is not likely to be resolved very soon. There isn't going to be a quick dismissal, although the charge is likely to be dropped/diverted down the road assuming this isn't a repeat offender and assuming he can stay out of trouble while the case plays out. But, his status as a football player is irrelevant to the court system. In fact, being a high profile athlete may actually slow the process down so it doesn't look like a favor is being issued for an athlete that your average defendant would not receive.
I think the bigger threat to continuing his college career at UT is the alleged shooting threat. Ten or twenty years ago it probably gets brushed off as thoughtless or angry, but meaningless, mouthing off. Today, authorities take this stuff very seriously---especially school administrators. There's no telling how this ends up.
