I made the mistake of promising a start to a player that otherwise may not be in the rotation. I have a few questions:

(1) Do promised starts continue in consecutive seasons? I guess it no longer shows up - but will I take a hit by benching him?
(2) If I can't bench him, what would be the consequence of withdrawing his scholarship? Do I take a hit reputation-wise?

Promised starts only apply to season after you signed the recruit.

You may take a hit on the reputation with cutting him.  If you have not cut any players yet, you may not notice a letter grade change because I think you get 1 or 2 cuts before you notice a letter change.  I know I have cut 2 players in the last 3-4 seasons lately and dropped to A- on my D3 team.

When you cut a kid you signed there's always a (very small) chance one of your other recruits will randomly transfer as well.

All of this discussion of cutting is irrelevant, because your answer to his initial question - no, you don't have to start him in later seasons - should mean he doesn't have to cut the guy.

Yup, I think I'll just bench him. The other information is very useful, though. Thanks!

When you cut a kid you signed there's always a (very small) chance one of your other recruits will randomly transfer as well.

Yes. Someone complained very vocally here on the forums many months ago about this happening. Apparently the guy cut the worst player he signed to his team after the player's freshman season, and his BEST player, who was evidently a junior with some potential still to be realized, sent him an email that said something like "you cut my homie so I'm taking my skillz elsewhere," and the coach was incredibly angry and ranted about not being able to cut a terrible player without the best player going away too. It was kind of funny but kind of sad because it is pretty dramatic to lose such a good player when you only wanted to get rid of a bad player as a strategic move.

Ouch, that's some serious locker room drama, haha. Fortunately the player I was thinking about cutting isn't really that bad - just not starter material.