Mats Hummels has denied that he has made a "promise" to join Manchester United in the summer.

Reports this week claimed that the £35m-rated Borussia Dortmund defender, reportedly Louis van Gaal's No 1 summer target, had given his word to Sir Alex Ferguson that he would join the Old Trafford club at the end of the season.

The 26-year-old, however, has since tweeted on his position.

"To clarify it: this supposed 'promise' is simply fictitious and that's the friendly formation," he wrote.

Manchester United's best XI of the season so far Show all 11 1 /11 Manchester United's best XI of the season so far Manchester United's best XI of the season so far David De Gea - 6.77 Never any doubt that the Spanish stopper would be in goal. Been brilliant this season. GETTY IMAGES Manchester United's best XI of the season so far Antonio Valencia - 7.24 Injuries have seen the former Wigan player deployed at right-back for much of the season and he comes out on top among the possible options. GETTY IMAGES Manchester United's best XI of the season so far Phil Jones - 7.46 Manchester United's defence was much derided at the start of the campaign but Jones has played a major role in silencing the critics and actually scores the highest of all Manchester United's players. Manchester United's best XI of the season so far Chris Smalling - 7.34 Alongside Jones is Smalling - another who's appeared more assured as the campaign has progressed. That centre-back pairing sees Jonny Evans and Paddy McNair miss out. GETTY IMAGES Manchester United's best XI of the season so far Marcos Rojo - 7.30 The Argentina international has begun to show why the club forked out £16m and allowed Nani to go to Sporting Lisbon to bring him to Old Trafford. Rojo scores much higher than his most direct competitor for the left-back berth, £27m signing Luke Shaw (6.80). Getty Images Manchester United's best XI of the season so far Ander Herrera - 7.24 The summer signing from Athletic Bilbao has shown an eye for goal as well as a pass this season, which is why despite playing less than Juan Mata (6.86), he snatches the right-sided midfielder position. Getty Images Manchester United's best XI of the season so far Marouane Fellaini - 7.34 Despite being mocked in some circles for his rough and ready style following his move from Everton, under Louis van Gaal, Fellaini has shown just how effective he can be which is why he claims a central midfield berth. GETTY IMAGES Manchester United's best XI of the season so far Daley Blind - 7.30 Alongside Fellaini is Netherlands international Blind, who scores higher than the alternative central midfielder, Michael Carrick (7.05). Manchester United's best XI of the season so far Ashley Young - 7.22 Despite an outlay of £59.7m on Angel Di Maria, it is former Watford and Aston Villa player Ashley Young who has done more to justify a place on the left side of midfield so far this season. After a lively start, Di Maria's performances have dipped alarmingly, leaving him with a score of 7.18. GETTY IMAGES Manchester United's best XI of the season so far Wayne Rooney - 7.36 The captain has been consistent throughout the season, despite being shifted from one position to another by an indecisive Van Gaal. Rates as Manchester United's second best player this season after Jones. GETTY IMAGES Manchester United's best XI of the season so far Robin van Persie - 7.21 Despite a stop-start season hit by injuries and exclusion from the team, Van Persie still scores much higher than on-loan Colombian Radamel Falcao (6.78), meaning the Dutchman claims the second striker position and completes the best XI of the season so far. GETTY IMAGES

Dortmund captain Hummels has come in for much criticism this season, with the Jurgen Klopp's side struggling in 10th place in the Bundesliga.

Hummels was an integral part of the Germany side which won the World Cup in Brazil this summer, appearing in six of the seven matches in the centre of defence.