Mats Hummels could do with a fresh challenge in his career according to Dietmar Hamann. The Borussia Dortmund defender continues to be heavily linked with a summer move to Manchester United which has been backed by ex-Liverpool and Manchester City midfielder Hamann.

The German believes his compatriot should make the move to Old Trafford and play under Louis van Gaal in order to really test himself after a successful career with Dortmund.

"He is interesting to many clubs. Hummels has had some great performances at BVB but a transfer makes sense for both sides," he said on German TV show Sky90.

"He has done everything with Dortmund. He is at a point where he needs a new challenge. Van Gaal wants him and United need someone who can build up their game.

"His era has come to an end. He has not played as well this year but he is still very successful. For both parties, it would be best if Hummels changes club this summer."