If you can get away with starting him, that’s the simplest way to get him his minutes. Set him to getting tired to start the season. He should be good for 16+ most nights, unless he gets in foul trouble. If he’s only getting to 13-14, you could bump him back to tired. Your frontline guy will still get the bulk of the minutes, so it shouldn’t hurt much to start him, especially since he’s got the talent level to hold his own.
If you don’t want to do that, the tricky part about coming off the bench is you have less control over his minutes. If the guy he’s behind has good stamina and is getting 25+ per night, it might be hard for the freshman to make 15. Most guys are ok with 13, but obviously the more the better. You could make him the first backup at both frontcourt positions, again set to getting tired to start, maybe down to tired against weaker opponents, and that should do it. You could also use target minutes. I do that a lot, especially early in the season, to fulfill promises, especially multiple promises.