Trainer on the field

[Reffing Rev.]

4th down. QB A7 (who earlier in the game was removed with signs and symptoms of a concussion, but cleared to return) scrambles to the right and throws an incomplete pass before getting roughed and landing out of bounds in his team box. Flag down, clock stopped for an incomplete pass, then for an officials timeout to administer a penalty. When I finish the penalty announcement, I turn to find the trainer on the field inside the hash marks with A7 and she starts running off the field. Her presence does not delay the RFP.

Does A7 need to sit out 1 down? The clock was not stopped for an injured player, and the trainer was not beckoned onto the field.