The attacking midfielder is being closely watched by the three Premier League big guns as they consider whether to launch bids when the window opens. Dembele is rated at £15 million by Fulham, where he has matured this season into one of the most accomplished playmakers in the Premier League. However, the Belgium international will have just one year left to run on his contract at the end of the season meaning the bidding for the 24-year-old will likely start at below the £10m mark. Fulham are keen to agree new terms with Dembele, who joined the Londoners from Dutch club AZ Alkmaar for £5m in the summer of 2010. But the west Londoners, whose highest paid player is goalkeeper Mark Schwarzer, know they cannot compete on wages or status with the likes of Liverpool and the two north London clubs, and will struggle to hold on to the Belgian if he receives an attractive offer. Dembele was initially signed as a striker but Martin Jol has played him almost exclusively in an attacking midfield role, including in a central two alongside Danny Murphy in recent weeks, and he has responded with some of the best football of his career. He has scored only six goals in 62 appearances for Fulham, including just once - at Wigan Athletic - this season and regular observers admit this has prompted question marks among those monitoring his development. \"His end product is an issue,\" one source told Goal.com. \"But if you play him in the right role with the right players he can make an impact.\" Jol is a big admirer of Dembele and has likened him to another left-footed schemer. \"In a few months, maybe a year, he will be like Rafa van der Vaart,\" said Jol last November. \"Dembele will learn and go on to become one of the best players in the Premier League.\"