I don't think he's ever coming back is the point. Some seem to think he will and are deluding themselves that he hasn't been quite a disappointment. There's good reason the price is so low.
15m for a 22 year old defender who’s played less than 20 games in the last 3 seasons? ( took a guess at the matches played). I don’t think that’s that low. IMO, very little chance of him coming back and he should move on, but definitely a missed opportunity.