Manchester City may be forced to ramp up their pursuit of an additional centre half should Matija Nastasic face a lengthy spell on the side lines.

The Serbian international, who formed a formidable partnership alongside Vincent Kompany at the heart of City's defence last season, is in a race against time to be fit for the new campaign after suffering an ankle injury in his side's 1-0 win over Sunderland in Saturday's Asia Trophy final.

There has been no confirmation as to how long Nastasic could be out for but an MRI scan will determine the length of his absence that will leave City will just two recognised centre halves in their ranks ahead of the new season.

The departure of Kolo Toure leaves just Kompany and Joleon Lescott as Manuel Pellegrini's central defence options, prompting speculation suggesting the Chilean manager will need to add another option to his squad. Real Madrid defender Pepe has found himself linked with a move to the Etihad Stadium in recent weeks, and the City boss has not ruled out further arrivals at the club before the transfer window closes.

"I said before that we could do something else before the Premier League starts but maybe we stay with the same squad," Pellegrini said.

"At the moment we aren't that concerned about that but I'm very happy with the squad we have. The club has spent money on important players.

"But you must remember that last year here there was Mario Balotelli and Carlos Tevez, so we had to replace two very good players.

"We have the rest of July and the whole of August to finish the squad completely. It's not absolutely complete but it's very near to being complete."

Nastasic suffered his injury playing on the sodden turf at the Hong Kong Stadium that has been decimated by rain throughout the duration of the pre-season tournament.

Tottenham Hotspur defender Jan Vertonghen was also a victim of the hazardous playing surface, damaging ankle ligaments during his side's 3-1 defeat to Sunderland much to the frustration of his manager Andre Villas-Boas.

Spurs are now unlikely to have the Belgian defender fit for the new season, a fate which could also face Nastasic and City, although Pellegrini insisted following the incident that the playing surface was not to blame.

"It wasn't the pitch though," the Chilean added. "He got a kick of his ankle but it was just part of the game."