It's actually the best news possible- Gronk is a monster and really, the only person that can stop him is him.
Because of his history and tendency to get hurt, whether genetic or from bad luck, I've always felt that his "party persona" while profitable and useful as a "brand," is very corrosive to his playing football.
I've read some of the comments, and FWIW, partying for the average individual does no real harm, but when your body is engaged in full battle every single week, trying to heal and repair from injuries, whatever you do to it is magnified.
Eating right, avoiding alcohol, and food with highly inflammatory properties, during the season, would really go a long way, and speed up healing. As is getting plenty of sleep (as opposed to partying all night long).