Mats Hummels could be on the move to Manchester United, after handing in a transfer request at Borussia Dortmund, according to reports.

German publication Bild is reporting the 26-year-old has fallen out with Dortmund boss Thomas Tuchel and is agitating for a move away from the Westfalenstadion.

It is understood United boss Louis van Gaal remains interested in the player who he tried to lure to the Red Devils in the summer of 2014.

However, Dortmund have moved to deny speculation that Hummels is unhappy in Germany.

"Everybody gets criticised, " Dortmund CEO Hans-Joachim Watzke said.

"But honestly, that massive criticism of the last days is unreasonably high in my opinion.

"Today I read of a problematic relation between Mats and us. But that's definitely not true.

"Mats Hummels is a very important player for us. He is our captain. I have an excellent relationship with him. Sometimes he is not too easy, but that does not have to be a disadvantage.

"He is a very decent guy, and we will support him entirely. There is nothing more to say about it."