Mats Hummels
Borussia Dortmund have confirmed Mats Hummels’s transfer request to join Bayern Munich ahead of the 2016/17 campaignGetty

Borussia Dortmund have been handed a massive blow ahead of next season after Mats Hummels, a target for Manchester United and Bayern Munich, submitted an official transfer request to depart the Signal Iduna Park in the summer and join the latter, who will be managed by Carlo Ancelotti next season. The German defender has been linked with a move away since last summer but with one-year remaining on his contract he has made the decision to move.

Hummels had indicated that he was losing sleep due to the difficult decision ahead of him but more than his departure, the defender's intention to join their Bundesliga rivals will be a dagger through the hearts of the Dortmund faithful. The German international, who came through the youth ranks at Bayern, has been with the Westfalenstadion outfit since 2008. He has been a target for the Red Devils since last summer but close ties to Munich will see the defender remain in his homeland.

Dortmund, however, have made it clear that they will not let him leave the club until the reigning Bundesliga champions meet their valuation of the player. They have also confirmed that none of the players at the club have release clauses, which gives them the advantage in negotiating transfer fees of their choice.

"Defender Mats Hummels of Borussia Dortmund has communicated his desire to leave the club in the summer and wants to join the league rivals Bayern Munich next season," read the statement on Dortmund's official website.

"Borussia Dortmund's board has subsequently decided to make such a change depending on whether Bayern Munich and Borussia Dortmund can agree a satisfactory fee. So far, Bayern Munich has not made an offer."

"As a precaution, it is pointed out that with Mats Hummels — as at present with all other players from Borussia Dortmund — no exit clause has been agreed and the player is logically tied to Borussia Dortmund until 30 June 2017," the statement added.