The young winger is attracting interest from several top clubs following his recent sparkling form but his boss believes that the 21-year-old\'s development would suffer if he left.Wigan manager Roberto Martinez has warned forward Victor Moses against leaving the club, insisting that it will inhibit his development.The Latics boss made the comments after the winger’s agent, Tony Finnigan, revealed that his client had turned down the offer of a contract extension, with his current deal expiring next year.However, Martinez believes that a move away from DW Stadium now would be a bad one for the 21-year-old Nigerian.“In the future, if he does the things that he has to do, he will be a top, top player,” the Spaniard told reporters.“But I don’t think it is healthy to start talking about his possibilities and his future.“I think Victor knows it and he is well aware to fulfil his potential he needs to work harder from now until the next 16 or 18 months.”Wigan have defeated Liverpool, Manchester United and Arsenal in recent weeks and Moses has been arousing interest from a number of clubs as a key part of that run.Martinez\'s men travel to Fulham on Saturday looking for their fifth Premier League win in six games.