World heavyweight champion Lennox Lewis is likely to announce his retirement at a news conference scheduled for a London hotel on Friday morning.
The 38-year-old Briton has not fought since successfully defending his World Boxing Council (WBC) title against Vitali Klitscho last June.
He has been given a deadline of March 1 by the WBC to confirm a rematch with the Ukrainian.
Lewis lost only two of 44 fights in a 14-year professional career after he won the 1988 Seoul Olympic super-heavyweight gold medal for his native Canada.
He became the WBC champion by default in 1992 when American Riddick Bowe threw the belt into a dustbin but lost the title two years later to Olivier McCall in the second round of their fight at Wembley.
In 1999 he became the undisputed champion with a unanimous points win over Evander Holyfield then confirmed he was the best heavyweight of his era by stopping Mike Tyson in the eighth round of a one-sided fight in Memphis in June 2002.