Gelsenkirchen, Germany (SportsNetwork.com) - Schalke announced on Wednesday that the club has completed the signing of defender Matija Nastasic after activating a transfer clause in his contract.

Nastasic was loaned to Schalke in January from Manchester City with the Bundesliga club having the option to make the move permanent.

And the club's general manager, Horst Heldt, has done just that, keeping the Serbia international in Germany.

The 21-year-old Nastasic has appeared in nine games for Schalke since arriving at the club, including both games against Real Madrid in the knockout round of the Champions League.