nEU players in Serie A

[DerKopite]

Basically, I've spent £28m on a Brazilian DM - a position that I really need filling. I'm AC Milan, and when I tried to register him, it wouldn't let me as it said that he needed to replace another nEU player in the squad. So, I sold Lincoln to Schalke and though that I could register him. Nope. It was saying that I could register him for the next game; whilst also saying he's taken up a nEU slot for the club but then saying that I couldn't register him for the same reason. I'm really confused; does anybody know what I have to do?