Ironically, Chisora was forced out of the original heavyweight fight when he fractured his left hand while sparring Ustinov.
The Russian is a dangerous opponent for Fury – especially on just four days notice – with his only professional defeat in 30 contests coming when he lost to Wladimir Klitschko's next opponent Kubrat Pulev by 11th round stoppage in 2012.
Ustinov is a heavy hitter with 21 KOs to his name and standing 6' 8" is a similar size to Fury who is listed just one inch taller.
'He has a decent right hand'
Discussions are also underway to reschedule Fury's fight with Chisora later this year in September.
Fury has been through a very difficult 18 months, with the cancellation of two fights with David Haye, before Chisora pulled out with injury on Monday.
Former Olympic champion Audley Harrison offered to stand in and fight Fury but was not considered after a serious of disappointing performances.
THE WOMAN FURY ACCIDENTALLY CALLS OUT ON TWITTER SPEAKS
- Sports & Recreation
- Kubrat Pulev
- Wladimir Klitschko