Junior dos Santos was initially scheduled as Volkov's opponent in the upcoming UFC Fight Night bout in Moscow, Russia, but he was forced to withdraw earlier Tuesday. According to Guilherme Cruz of MMA Fighting, dos Santos has been hospitalized with a serious bacterial infection.
Hardy asked for the replacement spot and UFC granted his request.
Volkov is 30-7 in his career with a recent win over Fabricio Werdum, but he lost his most recent bout at UFC 229 when he was knocked out by Derrick Lewis.
The Russian had a chance to reestablish himself as a contender in the heavyweight division with a strong performance against dos Santos, but he will now take on an inexperienced opponent in Hardy.
From the other perspective, this is an opportunity for Hardy to show he can be a legit competitor in MMA after his recent conversion from football. The 31-year-old officially has five wins in his professional career, all of which coming by first-round knockout, while he was also impressive in his other matches.
The only loss came by disqualification for an illegal knee, while his recent win was turned into a no contest due to a potential rules infraction.
However, none of the opponents have been at the level of Volkov, who is considered by UFC to be the No. 7 heavyweight in the world.
Adding in the short preparation and only about three weeks between fights, Hardy will have an uphill battle in November.