These include revamping the existing stadium, designing a more basic stadium that would be like an enlarged Premiership ground and removing elements like the offices and hotel.
"The most practical solution would be to delay the fit-out of non-core elements of the scheme, which would allow us to proceed and start the stadium," said the source.
The proposed changes come as Sir Rodney is due to meet David Moorcroft, chief of quango UK Athletics, to outline proposals for an athletics track at Wembley, which could scupper UK Athletics' plan for a £95m 43 000-seater stadium at Picketts Lock in north London.
An athletics track was part of the original design brief but shelved by Chris Smith in late 1999.
A decision on the design team for Picketts Lock is expected next week as UK Athletics and Lee Valley Park Authority await a decision from Wembley.