Sep. 29—STILLWATER — Oklahoma State running back Jaylen Warren crumpled to the ground and the entirety of Boone Pickens Stadium gasped. The emergent star of the OSU offense was reaching for his lower leg, in obvious pain last Saturday night against Kansas State — a game where Warren’s presence was greatly needed to seal a 31-20 Cowboy victory. When Warren went down with 7:12 left in the third…