I would say make it a type B obtuction and either protect him back to first or to second depending where everything lands. If it's a park that has tons of foul territory then he's probably going to second. If it's a tight field I'm keeping him at first.

Now change the play just a little. The throw is coming from third but up the line so the F4 goes for the back up immediately. He has a good chance of gloving the ball before it gets to the fence and they collide on the overrun. Is he now fielding or are you still protecting him.