Former West Virginia coach Rich Rodriguez bolted for Michigan just before the 2008 Fiesta Bowl, when Bill Stewart took over and coached until resigning amid controversy just before last season, when Holgorsen took over.
Though all those changes, Jeff Casteel stayed on as defensive coordinator. He left to join Rodriguez's Arizona staff last January, when former Oklahoma State assistant Joe DeForest took the defensive reins and made schematic changes.
“Some young guys have shown signs they'll be good, but as a group, we'll have to see,” Wallace said. “Coaches are trying to strengthen the recruiting on the defensive side.”
The Mountaineers also lack the depth needed to keep up with Big 12 offenses, many of which strive for upward of 80 snaps a game.
“If there's one thing we've learned from being part of the Big 12, it's that if you're gonna be running 80 or 90 plays a game, you really need some depth,” Wallace said.
OU co-offensive coordinator Jay Norvell said, “Week after week, you're gonna have to play against some very potent passing attacks ... We've got a good defense, and it's been difficult for our guys at times.”