The Argentinian opted for a reunion with former Blues boss Enzo Maresca at the Etihad Stadium with Xabi Alonso unable to bring in a new face on transfer deadline day.
Jordan Henderson has joined following a free transfer from Brentford alongside Fernandez's international teammate Valentin Barco.
However, the former Liverpool captain is expected to be out of action for another month, after suffering a broken arm on 2026 FIFA World Cup duty with England this summer.
Alonso does have have the option to dip into the free transfer market and he's rumoured to be considering a move for Henderson's old Reds colleague Gini Wijnaldum.
The veteran Dutchman, who won the Premier League and UEFA Champions League at Anfield, is currently without a club after leaving Saudi Pro League side Al-Ettifaq in June.
One player who is not expected to be a target is ex-Tottenham midfielder Yves Bissouma - who left Spurs as a free agent in June - with Alonso already reportedly turning down the chance to sign hm.