I think Sollied wouldn't want him back after all the trouble Dusan had with him.
However I think he could be extremely useful, probably playing 20-30 mins when we need these last minute goals.
I am sure Zio would be happy with this and he could just train for this role.
Zio is, together with Anastopoulos and Djorjevic, one of the most important players in recent Olympiakos history, and he should be given the chance to make amends for last year.