John Stones
John Stones is still an Everton player after Chelsea failed to meet their demandsGetty Images

Everton manager Roberto Martinez has revealed that he did not let John Stones leave this summer as there was not a single defender in the market who could have filled his shoes. The 21-year-old has emerged as one of the biggest talents in English football and has already got himself a call-up to the England national team.

Chelsea were heavily linked with a move for the player this summer with Jose Mourinho earmarking the defender as a like for like replacement for John Terry, who has started the season in questionable fashion. The veteran defender was sent off in their win over West Bromwich Albion, with the manager revealing that he has more faith in Kurt Zouma as he has pace and can hold a high line against the opposition.

Manchester United were also interested in the player but were rebuffed in their attempts to sign the defender, who has been valued at around £40m ($62m) by the club, as reported by the Guardian. Stones has started in each of Everton's games in the league and Martinez insists that he is ready to sell the player but only on the condition that he can find someone equally talented who can maintain the quality of the squad.

"We have very young players ready to kick on and it was about keeping that core," said Martinez, as quoted by the Daily Mail. "But you go from window to window and you say "OK, will we finish as a stronger squad? You assess. Players have moments of form, you look at ages. If we'd lost John Stones at that stage it would have been impossible for us to bring in a player of the same level.

"I've said before that every football club is bigger than any player but there is always a right moment and a wrong moment and for us to have our season we needed to have John — the same way that we needed Lukaku, Kevin Mirallas and James McCarthy," he added.