Muhammad Ali would have struggled to compete with much larger fighters like Tyson Fury, according to the boxing icon's former promoter Bob Arum.
The Top Rank founder has promoted both men during his career and the 88-year-old still promotes Fury in America, which led him to becoming WBC heavyweight champion by dethroning Deontay Wilder.
Arum also brought Ali to Arsenal's Highbury stadium in 1966 where he beat Henry Cooper in a rematch, and was also the promoter of George Foreman's comeback after 10 years away from the ring before the America went on to become the oldest-ever heavyweight champion in 1994.