According to the 'Daily Mail', Chelsea are in talks with former England keeper Rob Green.
The Blues are reportedly looking to bring Green in on a short term contract, as the third-choice goalkeeper.
Caballero is the second-choice goalkeeper, and Chelsea are still looking for a first-choice keeper in case Courtois makes the move to Real Madrid.
Sarri has been seen to show interest in Stoke City's Jack Butland and Leicester's Kasper Schmeichel.
Pepe Reina was also on the radar, but has since signed a deal with AC Milan.
Real Madrid are hoping for a £50million deal for Courtois, but have yet to agree terms with the Premier League club.