1. Injuries.

But mostly

2. Recruiting. Gundy doesn't really care to do it. Plus they have really whiffed the last 3 recruiting classes on the guys they did bring in.
3. Offensive coordinator isn't that good. He was actually let go a few years back but he is/was super popular among players. OSU was going to lose some really key players to transfer so Gundy brought him back.
4. Defensive coordinator isn't running the system that he would like because (see #2) there aren't they type of players that fit the system. So they are running a hybrid 3-3-5 and 4-2-5. But the DE's don't fit either mold and the lbers are terrible.
5. There was some internal strife this last offseason with NIL. Some players felt like they should get more. Effort seemed to match feelings.