Premier League clubs Tottenham and West Ham were selected Friday as the two final bidders to take over London's Olympic Stadium after the 2012 Games.
The Olympic Park Legacy Company said it will enter into final negotiations with the London rivals and complete a deal by March 31, 2011.
The legacy company previously said it wanted a commitment to keep the stadium running track as part of any bid, but Friday's announcement said the requirement could be waived for "a credible alternative."
Tottenham's application with American sports and entertainment giant AEG involves removing the track from the stadium. West Ham's joint bid with local borough Newham keeps the track.
"We started this process to ensure the very best legacy for the stadium, and we are now at a point where we have selected the two strongest bids," legacy company chair Margaret Ford said. "The stadium is a vital and vibrant component of the Olympic Park.
"Securing the most appropriate and viable solution is crucial for our long-term aspirations for the future Queen Elizabeth Olympic Park area."
The stadium will have an 80,000-seat capacity for the Olympics, hosting the opening and closing ceremonies and the track and field competition.
The stadium was originally designed to be reduced to 25,000 seats after the Olympics, but the bids by the Premier League clubs would mean having a capacity of around 60,000. The stadium is also part of England's bid to host the 2018 World Cup.
London Olympic organizers had promised to keep athletics as a primary legacy of the stadium when they successfully bid for the games in 2005, but all options are now open.
"The company is seeking a stadium solution that supports the intent of the London 2012 bid commitments for athletics or proposes a credible alternative," OPLC said.
Uncertainty over whether the track will be retained contributed to a decision last week by the British government and UK Athletics to withdraw London's bid to host the 2015 world athletics championships.
West Ham officials have long spoken of their desire to move from the 35,000-capacity Upton Park stadium to the London 2012 stadium, 3½ kilometers (2 miles) away.
"We are delighted to have been shortlisted for the next stage of the Olympic Stadium process," West Ham said in a statement, adding that it would "deliver the best legacy for the stadium by making it a busy, iconic center of sport, education and culture that benefits not just east London, but the nation as a whole."
Tottenham's expression of interest last month was a surprise since it had already been granted permission to build a 56,250-capacity ground adjacent to its current White Hart Lane home in north London.
Announcing its full-year financial results Thursday, Tottenham said it was considering the Olympic Stadium after a local government requirement to preserve four historic buildings had added 50 million pounds ($80.7 million) to the cost of a new ground.
White Hart Lane, 9 kilometers (5½ miles) from the Olympic Stadium, holds 36,310 fans but Tottenham sold out every Premier League game last season and has another 33,000 on a waiting list for season tickets.