England's World Cup warm-up matches and the Football League play-off finals for this season will not be played at the new Wembley Stadium.
Wembley was also scheduled to host the FA Cup final on 13 May
Old Trafford will now stage England's friendlies with Hungary and Jamaica on 30 May and 3 June because Wembley's construction may be delayed.
The Championship, League One and League Two play-off finals will take place at Cardiff's Millennium Stadium.
The Championship game is on 21 May and Leagues One and Two on 27 and 28 May.
"The Football League has exercised an option, negotiated in September 2004, to stage the play-off finals in Cardiff," said Football League Head of Communications John Nagle.
"The League's five annual showpiece finals will return to Wembley Stadium next season."
The play-off finals, Carling Cup showdown and the LDV Vans Trophy final all fall under the auspices of the Football League.
The decision to move England's games ahead of this summer's World Cup finals means that the Football Association will be able to take advantage of Manchester United's expanded 76,000 stadium.
The two corner quadrants are now almost completed - well ahead of schedule.
"We are delighted the FA have chosen to stage these two matches at the biggest club ground in the country," said a United official.