Mats Hummels
Hummels has made 18 appearances in the Bundesliga this season, but Dortmund have been hugely disappointingGetty Images

Manchester United are preparing a summer swoop for Borussia Dortmund duo Mats Hummels and Ilkay Gundogan, according to the Daily Mail. Both players are reportedly willing to leave the club after raising doubts over Dortmund's ability to compete in the big league.

Louis van Gaal is a huge fan of Hummels, who he has worked with during his time at Bayern Munich, and is banking on the German to shape his side's defensive woes, which if not for David de Gea's heroics this season, could have taken a massive turn for the worse.

The Red Devils have Phil Jones, Jonny Evans, Chris Smalling and Marcos Rojo to fill in their backline but need a leader to organise their defence, which has been shambolic at times.

Hummels, a regular for Dortmund and the German national team, would be a perfect fit to come in as a replacement for the legendary Nemanja Vidic and Rio Ferdinand, who formed the base for Sir Alex Ferguson's title conquests for the past few years.

The Dutchman is not leaving the midfield to chance either, with Gundogan also on the cards to come in as a long term replacement for Michael Carrick who is entering his mid-thirties.

The England international calms the United midfield and allows flair players like Ander Herrera and Marouane Fellaini to make their way forward and contribute attack.

Gundogan had a similar influence during Dortmund's progress into the final of the Champions League a couple of years back but his development has since been held back due to a back injury for which he missed the better part of the last two seasons and also the World Cup.

It will be a massive blow for the Bundesliga club who have had a forgettable season thus far and are looking resigned to miss out on Champions League football for the next term. Hummels is expected to set United back by a fee in the range of £36m while Gundogan, whose contract expires after the end of this season, can be made available for as low as £15m.