Sink or Swim, Foster will be getting major minutes game one. I have read many on here who seen him that think he needs some development and I appreciate the opinion and respect it. But, players with XF offers and ranking don't go to a school if they aren't expecting to play. Especially since his goal is to go pro early.
While I don't think Prohm promised him a starting spot right away I believe he did ensure him 20+ minutes with the opportunity to be a starter if he earns that. That is the reality of getting a top 60 recruit, and we've seen it happen with Georges through THT (top 80 guys playing major minutes by Dec)
As Sig noted for ISU to be good Foster figuring it out right away is the the most obvious path. We can pencil him in as the third big with a good chance at stating at PF in January.
here are the last 3 years of big 12 recruits over 6-10 and their freshman stats