Player ineligible , I have the ingame editor but dont know how to make him eligible

[kieron666x]

So I signed a new midfielder from coventry , my biggest transfer of this save, I get him and its saying he's ineligible since hes apparently already played for another team in one season, despite the fact that I cannot see this in his history? Am I just an idiot? What am I missing?

Is there a way to alter his history with the editor so he becomes eligible? Just bought it but ive never used it, 

Thanks