The young England midfielder continues to impress this season and the Toffees boss suggests that they have "two to three years" before he will need to go to a bigger club.Everton manager Roberto Martinez expects Champions League contenders to start sniffing around midfielder Ross Barkley and believes he could follow in the footsteps of Gareth Bale.
Bale left Tottenham for Real Madrid last summer in a record 100 million pound deal and the Toffees boss sees similar quality in his young playmaker, suggesting he may have "two to three years" to achieve all that he can at Goodison Park.
Asked by reporters if big teams might chase Barkley, Martinez agreed, saying: "And it would cost them a lot of money. He is as good an English talent as we've seen and that's going to alert teams competing to win the Champions League, never mind the Premier League. He's got the potential to achieve what Bale did.
"Once a player fulfills his potential and has done everything at a club, it's not positive for anyone to keep him because he's then not going to produce the kind of performance the team needs.
"The most impressive thing for me is his character. Nothing and no one upsets him in a game, even if some opponents try to. We don't produce many players with that mental discipline, unfortunately. It's the biggest factor he has. I am reminded of [Andres] Iniesta and Xavi, players with that mentality and character.
"Ross has got everything to be as good as he wants. He is the perfect fit for Everton and the perfect fit for what we want to do in the future. We want to build the team around him. At the moment, he needs to keep playing at Everton and, hopefully, we can use his development to take the club forward so that we don't have to lose him. That's the next challenge for us."
Barkley has taken his first steps into a senior England career this season and continues to make his case for inclusion in the World Cup squad, though Martinez suggests it would be best if he went to Brazil as an important first-team figure rather than a backup.
"If you go to the World Cup and don't play, it's a good experience but probably you could use that time better, regenerating and refreshing," he said. "Ross is ready for whatever England manager Roy Hodgson thinks he needs him for. If he's got an important role, it won't faze him; if it's just a small part, he'll be ready too.
"If Roy feels it's not his time, he'll be happy to support England from a distance and prepare for next season. I respect Roy and he's got his own ideas."