​Everton manager Roberto Martinez has admitted that the club could lose winger Gerard Deulofeu in the summer due to the buy-back clause inserted into his contract as part of the deal which brought him to Goodison from Barcelona this summer.





The Spanish winger has been in excellent form for the Toffees so far this season, contributing a goal and five assists in his five Premier League starts since his move in the summer's transfer window.





Deulofeu is now in his second spell with Everton, having impressed sporadically on loan during the 2013/14 season as part of the club's top four push, which saw them eventually finish above Manchester United and Spurs in fifth place.





Martinez revealed that Barcelona could not buy the player back in the January transfer window, but could make a move in the summer if he continues to impress.





Quoted on ​Sky Sports, he said: "There is nothing we can do if they activate the clause. That was the deal and the only way we could access the player in the terms that we wanted. I'm delighted with the deal. There are certain things in the deal. It is 9m euros for the first year and 12m euros in the second year.





"They can't take him back in the winter so they can't take him back in January. My worry would be to lose him in January. That would be a big problem. But for us to have a player of that quality for the money we paid, if we lose him it will be on a profit financially so we would be able to use the money.





"You're talking about a Barcelona player who has been all through his years as the golden boy believing he is going to be at the top level at Barcelona and we got him for a very good price. You want the player. I would like to tell Barcelona that he's rubbish but they come to watch our games."