This feels like a non-starter to me, he wanted to leave to better his career and presumably took a big pay rise to do so.
Why would he come back when we're a worse career move than when he was here before, and can't offer him the same money he was on before?
If there's any possibility we could though, then we absolutely should. Souttar, Tanganga and Anel would be a ridiculous set of centre halves for this league, and would even work as a back 3 with the ready made wingbacks we also have, if we wanted to have that set up as an option.