Celtic manager Neil Lennon has blamed an agent\'s fee as the reason why club captain Scott Brown has not yet signed a new contract.The 26-year-old can walk away for free at the end of the season and can begin talking to other clubs from January.He is currently out of action with an ankle injury that could keep him sidelined until the New Year.Before suffering his latest problem, Brown had made four appearances for the Hoops in the Scottish Premier League and they have since fallen 12 points adrift of Rangers.Lennon insists that the midfielder is keen to stay at the club but the delay is down to the player\'s agent.He said: \"I don\'t think it is a major concern but I think it\'s going to become a case where we need to sit down and see what he\'s thinking.\"Everything has been agreed but there is a discrepancy with the agent\'s fee. From what I gather it\'s the size of the fee.\"I don\'t know the details but I believe the player has agreed terms but the fees haven\'t been paid yet, or settled on.\"