Chelsea have reportedly completed their first signing of the summer but will not confirm the identity of the incoming player until July 1.
The Premier League champions have been linked with the likes of Romelu Lukaku, Tiemoue Bakayoko and Kalidou Koulibaly this summer, with manager Antonio Conte reportedly keen to make up to six new signings.
The Evening Standard reports that they have already finalised terms with one new player, but have decided to delay the announcement until the transfer window officially opens on July 1.
Chelsea are in the market for a backup to Thibaut Courtois following Asmir Begovic's £10m move to Bournemouth and reportedly see 35-year-old Caballero as the perfect option to provide competition for the number one jersey.
Caballero made 27 appearances across all competitions for Man City last season, 17 of which came in the Premier League.