Wigan boss Roberto Martinez has warned Birmingham, Sunderland and Arsenal that he "does not want to sell" his star players this summer.[LNB] Martinez is not surprised that the star members of his squad are attracting transfer interest - but he is 'hopeful' that there will be no sales.[LNB]Birmingham and Sunderland are both understood to have contacted DW Stadium officials regarding Charles N'Zogbia, while Italian giants Juventus have also been linked with the wide-man.[LNB]Hugo Rodallega has admitted in the past that he would relish the chance to play for Arsenal, while Mohamed Diame's impressive 2009/10 campaign has led to speculation linking the midfielder with the Premier League's top clubs.[LNB]But Martinez wants to keep the core element of his squad and is hopeful that chairman Dave Whelan will not want to accept what would be a large transfer income from any sales.[LNB]The Latics boss told the Wigan Observer: "I am hopeful but you can never be confident about things like this. [LNB]"We have got a very good group now and the players are at an age where I don't think they have fulfilled anywhere near their potential yet. It would be too early for anyone to leave the club.[LNB]"As well as Hugo and Charlie, there are a group of four or five players who have performed so well that I wouldn't be surprised if other clubs were interested in them.[LNB]"I feel that every player here has another level to reach with us, and the players know that. If we keep attracting attention from other clubs it is because we are doing something right which is a positive."[LNB]Martinez added: "We all enjoy watching Charles play, and I really feel he has another level to find with Wigan.[LNB]"I have got no doubt that we have got six or seven players who can be as good as they want to be in world football.[LNB]"But they are still young and they think they can develop together by staying together.[LNB]"I am talking about players like Momo Diame, James McCarthy, Victor Moses, Hugo Rodallega, Charles N'Zogbia, players under the age of 24.[LNB]"That is a huge strength for us, and we have time on our side in that respect.[LNB]"It would be impossible for us to replace Charles or Hugo, and that's why you need to develop other players.[LNB]"With the values in the modern game, it would be impossible for us to replace either of those two players. We don't want to sell our players, and that will never be the position.[LNB]"The only time that will change is when the player feels he has done everything at this football club and he needs to move on to the next challenge.[LNB]"To do that, he would have to go to the top four, or to a big club in Europe."