Mata has twice been an unused substitute for the Blues in the Premier League this term, and was withdrawn before the 65-minute mark on both of his starts against Aston Villa and Everton.
That's prompted reports that claim he's no longer first-choice at Stamford Bridge, and with a World Cup on the horizon, Mata has been linked with a move away from Chelsea.
And Eurosport claims Manchester City - with their wealth of Spanish talent - could be an attractive option for the former-Valencia playmaker.
Manuel Pellegrini brought Jesus Navas and Alvaro Negredo to the Etihad Stadium from La Liga this summer, the two Spain internationals joining the likes of David Silva, Javi Garcia and the Spanish-speaking Argentina international Sergio Aguero.
But Chelsea boss Jose Mourinho has publicly stated his desire to keep Mata at Stamford Bridge.
The 25-year-old was a key player for the team last year, and is a two-time Chelsea player of the year.