Schalke chief Horst Heldt is stepping up their pursuit of Manchester City defender Matija Nastasic.

Kicker says Heldt hopes to tie up a deal for the Serb this week, with the view to announcing the player's arrival before the weekend.

Nastasic has been identified by Schalke coach Roberto di Matteo, the former Chelsea manager, as an ideal addition.

"Yes, we're working on it. Our coach Roberto Di Matteo has put him in his plans.

"Also, the player wants to help us," said Schalke chairman Clemens Tonnies.