Chelsea have targeted Zenit's Ezequiel Garay as an alternative central defensive option if they do not get Everton's John Stones, sources have told ESPN FC.
Although the 21-year-old English centre-back remains Jose Mourinho's primary target for the remainder of the window, Everton have only dug deeper in their refusal to sell the young defender.
Mourinho had previously challenged the Goodison Park club to say that Stones is not for sale at any price, and chairman Bill Kenwright has responded by doing exactly that and rejecting the player's transfer request, as revealed by a statement released by the club.
"Since the start of the transfer window, we have resolutely turned down offers from another Premier League football club for our player," Kenwright said.
"John is not for sale and he will remain a highly valued member of our first-team squad."
Chelsea had already initiated a contingency plan, however, and have been in contact with Zenit about Garay for the past week.
Although the Russian club have put forward a similarly resolute stance as Everton, the English champions feel a deal for the 28-year-old Argentine would be easier to do, especially since he is also represented by Gestifude -- the agency of Jorge Mendes, which counts Mourinho a client.
As it stands, however, Chelsea have not given up on getting Stones. They may yet find competition from Manchester United, who are willing to offer Everton cash as well as an immediate replacement in Johnny Evans or even Phil Jones.