I haven't tracked every team, just pointing out that it's going to be a weird year. OSU has three guys in CJ Walker, Jimmy Sotos, and Kyle Young who would otherwise be in their last year. Now, they...might be in their last year. OSU would only have one true point guard on the team next year, so Holtmann has a lot of motivation to tell Walker to stick around. Further, where are they going to go? No NBA team is interested in CJ Walker and for guys like Young and Walker do you want to have another year of college and basketball or maybe try to chase the G League or Euroball.
No doubt some guys will leave and some guys will get shoved out the door, but veteran teams might become really veteran teams next year. If everyone returned for OSU they would have 8 seniors. Wiscy (I think) starts five seniors and none of them have to leave.