This player was forced into my club and now I can’t get rid of him.

You can convert it to staff and release it

estac: Tu peux le reconvertir en staff et le libérer

Yes, if he's available for retraining, because I'd already had the case, and I couldn't retrain him as a member of staff.
Aymeric has set up a security system to avoid reconverting players immediately after they have been bought, to avoid money transfers.
Ask an admin if he can delete him in a few days if you can't convert him back.