Manchester United have received a massive blow in their pursuit of Mats Hummels after Borussia Dortmund took him off the market to consult with new manager Thomas Tuchel in the summer, according to the Daily Mirror.

The Red Devils have already made a £21.5m bid for the defender but Jurgen Klopp's exit has forced Dortmund's hand, who now want to keep their new manager in the loop for any transfer decision.

Tuchel, who has signed a three-year contract with the club, will take over after the departure of Klopp, who has won two Bundesliga titles with the Germans but a disastrous season has seen his credibility questioned among fans.

The management therefore wants to put their weight around the new manager and has asked United to wait until the summer for their decision, as they do not want to disrupt the harmony in the squad at this point. Louis van Gaal is a huge fan of the player, having worked with him during his time at Bayern Munich and has earmarked him as the missing piece to a title challenging squad next season.

Hummels will add some much needed stability at the back for United, who have been forced to mix and change their defenders owing to injuries or suspensions. The departure of Rio Ferdinand and Nemanja Vidic has left a gaping hope at the back and the Dutchman is looking to induct Hummels as the leader in the team and organise their defence.

Hummels currently has two years left on his current contract, which would make it very difficult for United to force their hand unless the German pushes for a transfer himself. However, with no Champions League action at Dortmund to look forward to, the defender may be willing to shift to greener pastures and add another dimension to his game in a different league.

United are also closely monitoring the situation unfolding behind Ilkay Gundogan at Dortmund and may choose to make a double swoop in the summer.