The 25-year-old German international is a player that for the last three years has found himself constantly linked with a move to Old Trafford.
In light of Louis van Gaal's appointment, rumours have once again surfaced and according to talkSPORT's Dutch expert a move this summer could be on the cards.
'Van Gaal has a favourite centre-back,' said van der Kraan.
'He's been really impressed by Mats Hummels over the last two years.
'I would certainly think he's a very strong candidate to come to United. He might not be a really fast defender, but he is the kind of guy who can play football.
'Van Gaal likes to start his football at the back. He wants to play with a central defender who's big, tall and can pass'
Hummels is a well-known and well-respected defender and after finishing outside the European places in the Premier League, his signature would have to be classed as a huge coup for the Red Devils.
We take a look at three questions that may be asked if he does decide to sign for United and the reaction from Manchester United supporters on the speculation.
Who would be the best current Manchester United defender to play next to Hummels?
The Borussia Dortmund defender, in my opinion, plays a similar style to Phil Jones. He is a very good footballing centre-back, commanding in the air, strong, but relatively slow in the foot-race. I would fancy, if he was to sign and no-one else comes in, for him to start at the back with Chris Smalling, a player who could offer that bit of athleticism that may be lacking otherwise.
How good is Hummels, can he emulate Rio and Vidic at their best?
The onus and expectation on Hummels would be evident from day one. I feel that he would need to hit the ground running if he is to be a success, and the same goes for Louis van Gaal. I believe he, and van Gaal, both have it in them to be a huge success at United but a slow start could incite media pressure.
Should United look to sign Sokratis as well, in order to keep the partnership together?
The €9.5 million signing from Werder Bremen has arguably been the bargain of the season in the Bundesliga and was named next to Mats Hummels at centre-back in the Team of the Season. A known physical and athletic defender, he has gone on to prove himself amongst the league's best and in their current form, the partnership of Sokratis and Hummels looks to be one of the best in Europe. Dortmund would be extremely reluctant however to lose both.
I hate these rumours so much, although if we get Hummels ill scream so much! :)) #MUFC— (@AmanSinghJandu) May 19, 2014
Would actually love it if we signed kroos and hummels #MUFC— Harry Johnson (@Harry_Johnson15) May 19, 2014