If you can be bothered with all of the special training, I would make him a LB/RB. Train him with versatile and dribbler (as well as all the other usual LB/RB training you would do), give him a lot of duelling and he should give a fair few assists each season, as well as being a strong defender.
Numpty’s suggestion is also valid, but he will always have a low star value and never play for the NT in case you were hoping for that to happen. If you’re prepared to sacrifice this chance, then I see no problem with doing this with your player.