It's a torn hamstring - PRP's not a temporary fix. He's not trying PRP thinking he'll come back, play for a bit. and then get surgery. It either repairs things to the point he doesn't need surgery, or it doesn't fix it well enough for him to play at all. I imagine he hopes it fixes it well enough for him to DH or whatnot, and then 4 months of offseason gives it time to heal the rest of the way.