The 21-year-old Serbian, who impressed in his first season at the club after his switch from Fiorentina, suffered a miserable 2013/14 after a mysterious knee injury confined him to the sidelines for much of the campaign.
His status as an under-21 player is an advantage this season. He can be included in City’s Premier League squad without affecting their quota, but according to Chris Wheeler of the Daily Mail, he could be sold if Mangala arrives.
Much will depend on whether or not the club decides to send Karim Rekik on loan again in order to continue the progress he made at PSV Eindhoven last season. Rekik, who is highly rated by City’s technical staff, impressed in the Dutch Eredivisie, and it would make sense to allow him to spend another season as a regular at a team in Europe rather than expect him to fight for his place at City.
Manuel Pellegrini is yet to see the best of Nastasic. His injuries led to an alarming dip in form that saw the unruffled, classy style that characterised his first season at the club (when he was only 19) replaced by a nervousness and a lack of strength.
But it’s still clear that he is a very talented player and could well end up as one of Europe’s top defenders with the right guidance. It’s perfectly normal for a young player to suffer a dip in form, but it’s now a question of whether he can return to the level he is capable of when he gets his next run in the side.
The expected arrival of Mangala would restrict his appearances, with the Frenchman almost certain to partner Vincent Kompany at the heart of City’s defence. Martin Demichelis, fresh from his World Cup final appearance with Argentina, would then be the Belgian’s first replacement given both are right-footed, leaving either Rekik or Nastasic as direct competition for the left-footed Mangala.
Dedryck Boyata recently signed a new deal, but he has rarely shown he is capable of becoming a regular first-team player at City and is there, in truth, because of his home-grown credentials more than his ability.
And with the club’s net spend this summer restricted to £49 million after UEFA imposed sanctions on the club for failing to comply with financial fair play regulations, it seems Nastasic, whose reputation as a fine young player would see him fetch a decent fee, is being considered as a possible departure to fund other purchases.
It’s a move which in the short term may make sense, but one which City could end up regretting if he fulfills his huge potential.
Roberto Mancini’s final summer transfer window in charge at City was defiined by an ill-thought-out, scattergun approach to signings, many of which failed to justify their price tags. Nastasic, though, was the exception to that rule, having made his debut away at Real Madrid in style and continuing to impress throughout the season.
He was oddly composed for a defender so young, breezing through matches with an air of confidence and calmness. His reading of the game was excellent, and his ability to produce classy-looking slide tackles dazzled the City fans.
His performance level dropped significantly under Pellegrini—surprising given almost every other player in the squad appeared buoyed by his arrival—but he can become a great player with the right management. Very few 21-year-old centre-backs have shown his level of maturity.
It may seem sensible to cash in now, but City would be likely to regret selling him if, indeed, he was ushered out of the exit door this summer.
Rob Pollard is Bleacher Report's lead Manchester City correspondent and will be following the club from a Manchester base throughout the 2014-15 season. Follow him on Twitter here: @RobPollard_.