Borussia Dortmund boss Jurgen Klopp will do all he can to keep Manchester United target Mats Hummels this summer. The German international has been strongly linked with a summer exit from Borussia Dortmund after both Barcelona and Manchester United were credited with interest. Hummels has struggled this season with injury but his impact at Dortmund in recent seasons has seen him heralded as one of the best defenders in European football. A move to Barcelona had been tipped with their need to sign a centre-back growing bigger and bigger as the weeks develop. However, Louis van Gaal’s recent arrival at Man United has seemingly put them in pole position for a potential summer move. Van Gaal is widely known for his capability of attracting the biggest players and it is understood that Dortmund boss Klopp is now doing all he can to convince Hummels to remain with the Bundesliga club. Jurgen knows that Man United have been interested but he is more concerned now that Van Gaal is in charge. a source close to the club told us.