Last season when you look at the stats with him in the team:
P32 W22 D7 L3 PPG 2.25
Versus those without him:
P13 W2 D6 L5 PPG 0.92
(I must have missed one game but I'm too lazy to go back and check where it sits)
Multiply those points per game over a full season and its the difference between a team getting relegated (if nobody had points deductions) and a team winning the title.
Zemura is the last player we should be looking to sell right now, both given the influence on results having him in the team seemed to have and because we don't have anyone else that can play there.
He may only have a year left on his contract but he's under 24 so won't be leaving on a free at the end of it, should he decide not to extend.