Chelsea are set to step up their interest in promising German winger Julian Brandt after he turned down a new deal at Wolfsburg. The 17-year-old who has attracted the interest of Bundesliga giants Bayern Munich and Borussia Dortmund was offered a long-term contract to remain at the Volkswagen Arena. However Brandt has decided to see out his current deal which expires next summer as revealed by his club. "Julian Brandt has turned down the offer to sign a new contract with VfL Wolfsburg" a Wolfsburg spokesperson told Deutsche Presseagentur. "As he is out of contract at the end of the campaign Julian Brandt will therefore depart from VfL Wolfsburg." Chelsea boss Jose Mourinho is keen to secure a deal to bring Brandt to Stamford Bridge and will step up his efforts to beat Munich and Dortmund to his signature.