Mats Hummels
Mats Hummels has once again been linked with a move to Manchester United Getty

Manchester United have rekindled their interest in signing Borussia Dortmund star Mats Hummels, according to talkSPORT.

The 20-times English champions are looking for a central defender in the summer transfer window and had set their sights on the German international. However, he reportedly rejected a chance to make a switch to Old Trafford after delay from the Red Devils in completing the move.

Hummels is back on Louis van Gaal's radar and he is expected to leave the Bundesliga outfit. He has already informed Dortmund about his desire to leave the club as he wants to join the English side.

Jurgen Klopp left Dortmund following the end of the 2014/15 season after they finished seventh in the league table and lost to Wolfsburg in the DFB-Pokal final in May. His departure has forced the centre-back to consider his future at Signal Iduna Park.

Dortmund have struggled to challenge league rivals Bayern Munich and will not feature in the next season's Champions League. His employers' failure to challenge the German champions has made Hummels unhappy, which has forced him to consider his future.

The player has two years left on his contract. United need a centre-back and are set to make an offer next week as a bid of £20m ($31.1m) will see Dortmund part ways with Germany's World Cup winning defender.

Any move from United has to be quick as Hummels is also attracting interest from AC Milan. The same report claims the Italian giants are also in the frame to land him.

Dortmund chief executive Hans Joachim Watzke had earlier confirmed the club are expected to see two star players leave. With Hummels likely to be one of those players, his compatriot and midfielder Ilkay Gundogan could be another player to depart in the summer transfer window.

Gundogan has also been linked with a move to United as he has just one year left on his contract.