There's no way they can have an enforceable policy on something so many guys do.
It falls in the "Never give an order that won't be obeyed" category, imo.
It looked like he reinjured it during a successful 3rd down run earlier in the game.
He started altering his handoffs when running to the right for several series.
He may have taken the needle at halftime.
I just want to quote this so more people see it.
His mental game has become among the very best in the world over the course of this year.
Huge props to both him and his coaches.