London's Olympic Stadium is set to be confirmed as a venue for matches at the 2015 Rugby World Cup - but the retractable seating may not be in place for the tournament.
England 2015 RWC chiefs have been assured that construction work on converting the stadium will have reached the necessary point in time for the tournament in two years' time.
The London Legacy Development Corporation (LLDC), which owns the Olympic Stadium, has not been able to offer guarantees that the retractable seating that covers the running track will be in place. But it is understood by Press Association Sport that, that is not viewed as a major issue for rugby union given Italy play their internationals at the Olympic Stadium in Rome, complete with running track.
The announcement at Twickenham on Thursday will mean a number of Rugby World Cup matches - perhaps even as many as five - will take place at London's Olympic Stadium before West Ham move in as tenants in 2016, and further building work will take place after the Rugby World Cup to prepare for football.
In order to speed up the work and get an early start to prepare for the World Cup, the LLDC has decided to appoint sub-contractors for steelwork, electrical and mechanical work before the main contractor.
LLDC sources say building work should begin as soon as the athletics event marking the first anniversary of the London Olympics in July is over.
Manchester City's Etihad Stadium is also set to be named as a venue - Old Trafford was withdrawn by Manchester United from the shortlist due to concerns over the effect the rugby matches would have on the pitch.
The announcement should also confirm that Twickenham and Cardiff's Millennium Stadium will split the quarter-finals, with the London venue hosting both semi-finals and the final.
The long list of 18 venues originally selected by tournament organisers contains 13 football grounds, including Wembley Stadium.
Apart from the Olympic Stadium, the rugby grounds are Millennium Stadium, Cardiff; Kingsholm, Gloucester; Twickenham Stadium, London; Sandy Park, Exeter. The Rugby World Cup will have 48 matches in all - 40 group matches played by four pools each of five countries, four quarter-finals, two semi-finals, a third-place play-off and the final.