Connor Williams is the poster child of Big 12 offense and they reached for an OT to play OG.
The Spread Offense was created because of the lack of OL and the name schools gobbling them up. The emphasis had to go from size and strength to agility. Williams was an athletic OT at UT, he was supposed to bulk up and get stronger to play OG in the NFL and that hasn't happened and it doesn't most of the time. If it was that easy, they'd be doing it a lot more. Just get a bunch of 6'3" guys and feed them like geese and put them in the weight room.
He was the weak link before the injuries hit but now he's just part of the overall problem, one really good OL that can play.
OL is just one of the challenges facing this team in the off season.