Not necessarily, I really think that Prohm is focusing on Arlando Cook, Emmanuel Malou and Romello White and has Carter. Plus I'd be surprised if the staff doesn't try to add one more JC or immediate transfer post player with or with out TC. Cook would have an opportunity to earn a starting spot, but from watching him I am not sure he is physically ready to start in the Big 12 day one, like most HS post prospects outside the top 25-30. it isn't a given he'd be the starter. Iowa only has one scholarship available thus his track to playing time is pretty clear as of today.
Physically he is ready, IMO. He's got a very good build, he's 6'8" and seems to be pretty athletic.
If he wouldn't start, it would be more because he's not yet highly skilled, although as McKay and many other big men have proved, you just have to be able to run up and down the court and finish if you're 6'8"+.