The squad is top heavy for centre backs. I guess that as no one is likely to come in for Kean or Holgate, Mina would be allowed to leave if an offer came in. Is it worth keeping him anyway now we have just signed a defender who will hopefully play/be available most matches? Now we can give Mina rests and take better care of him.
My view is unless we get a decent offer, for him we should keep him at least until January, if we aren't offering him a new contract (which we'd be mad to do, given his injury record last season).