Today I thought of the possibility of an existence of a correct sentence that has the following words "in the next", because it seems to me now not logic to have such sentence since it has a needless preposition. For example:
He'll be at the university in the next semester.
It seems the preposition "in" is really needless here. But my question if it's considered ungrammatical and not natural, or both are considered grammatical?
N.b. It somehow sounds to me like "in the afternoon" that already has one preposition (after). I mean to my non native English ears it sounds much more natural to say "I'll be there afternoon." than to say "I'll be there in the afternoon.".