Schalke are close to agreeing on a deal with Manchester City to sign defender Matija Nastasic, according to the German club's general manager Horst Heldt.
The Serbia international, 21, is out of favour at City under Manuel Pellegrini, having not made a Premier League appearance this season.
Heldt told Germany's Sport Bild magazine that a deal could be done within days.
He said: "We are negotiating back and forth, that's how it goes. You get closer and closer and in this case we are no longer far apart from each other. I am optimistic that we will get this done in the coming days."
Heldt added the deal would be "a loan with an option to buy."
Nastasic joined City from Fiorentina in 2012, signed by former boss Roberto Mancini. He made 13 league appearances last season as City won the title, but his only outing this term has been in the Community Shield in August.
Schalke are coached by former Chelsea boss Roberto Di Matteo.