Matija Nastasic enjoyed a productive debut campaign in England, with 30 appearances made for Manchester City in all competitions.
He was, however, to see injury limit his involvement during a successful Premier League title bid in 2013/14.
The 21-year-old has now slipped further out of favour, with big money spent on France international centre-half Eliaquim Mangala over the summer.
Manuel Pellegrini is yet to select Nastasic in top-flight competition this season and he finds himself edging towards the exits ahead of the January transfer window.
Bundesliga side Schalke are among those to have expressed an interest in the youngster, and they are confident that a deal can be done.
Schalke chief Clemens Tonnies told BILD: "Yes, we are after him. Our coach, Roberto Di Matteo, has him in his plans. Also, the player absolutely wants to come to us."
Nastasic is under contract in England until 2017, so he would not come cheap.
He is a player with plenty of potential still to be unlocked and was tipped for a bright future after settling quickly at City.
There is, however, little point in Pellegrini keeping him on if he is not going to figure in his plans and a New Year deal may be the best option for all concerned.