Might be because he’s played for 2 clubs this season so wouldn’t be able to play for another.
If that’s the case his options were either he gets payed off, sits at home and trains on his own as no other club can sign him. Or…earn the same money whilst training within a professional club setup every day with the (very!) slight chance you might make the playing squad.
Don’t really blame him for staying, the blame should be on whoever gave the man a 2 year contract!!