It is understood the practice has been asked to draw up plans for a much shorter 14-storey scheme - the same size as Grimshaw's original proposals for the site which received planning consent more than five years ago.
The current speculation about the project is the latest in a long line of rumours which have surrounded the 217m skyscraper in the city of London since it was submitted for planning in the summer of 2002.
The scheme was finally approved in January 2004 but with the lack of any obvious progress doubts still remain as to whether the development will get off the ground.
Even so Grimshaw and Minerva have continually denied the overdue project has been shelved, most recently in September last year when the developer hit out against similar claims (AJplus 21/9/05).
However the scheme has not been welcomed by local residents and a smaller tower would be likely to meet with less heated opposition.
Despite the gossip the developers have insisted Grimshaw has not been asked to come up with any new proposals, maintaining that a 14-storey block has always been one of the two options still under consideration for the St Botolph's Street site.