I get people saying look at Mahrez, Sane, etc their first year here and how long it took them to adapt to Pep's system, but there are massive differences between Marmoush and those two.
Sane was a 20-21 year old who was incredibly raw but you could see the talent and that what he really needed was refining to become the player he ended up becoming for us. Marmoush is 26, going on 27. The likely hood that he is going to develop the necessary tools at this point is very minimal.
Mahrez was a case of him just having to learn the system and play our way. You could still see the talent and quality of him and what he had to do was just understand the system better. Marmoush seems to have this problem as well but you then compound it with the technical flaws in his game, I am just not sure he will be able to figure both out.
In both Mahrez and Sane's cases by the end of their first seasons you could begin to see they were starting to figure it out. Marmoush looks more like a case of, I don't know if he has the quality to play here, and I don't know if he will be able to develop it at this stage of his career.