Saracens have decided to play their Heineken Cup quarter-final match against Ulster at Twickenham.
The competition's rules state that a team hosting a last eight game must provide at least a 15,000 capacity ground - 5,000 more than is available at Allianz Park.
The Men in Black's preferred choice was to extend temporarily the current seating at their new home but that option has been refused by the local council.
Club chairman Nigel Wray told the club website: “We look forward to playing this important match at the home of English rugby, a ground that many of our players know extremely well.
"It is absolutely clear that people want to see big teams playing big matches at big stadiums, and that is precisely what we will deliver at Twickenham.
“We did consider the option of playing this showpiece match at Allianz Park, our brand new home stadium in NW4, but, in consultation with local residents and our partners at the London Borough of Barnet, we have decided to settle at the new venue before applying to stage a one-off event with a larger capacity.”
The crunch match will take place on Saturday April 6, with kick off at 6.30pm.