The UFC’s return to Russia has a new main event after Aleksei Oleinik was tapped to replace Alexander Volkov in the headline fight against Alistair Overeem on April 20 in Saint Petersburg.

Sources close to the contest confirmed the news on Wednesday following an initial report from ESPN.

There’s no word on what happened to Volkov but it appears he was pulled from the card and the UFC sought out a replacement to face Overeem in the main event.

Oleinik steps into the fight with a 4-1 record in his past five fights including submission victories over Mark Hunt, Junior Albini and Travis Browne.

The crafty ground specialist has quietly been creeping up the rankings in the heavyweight division and now he’ll face a former title contender in Overeem when they clash on April 20.

Overeem comes into the fight off a TKO victory in his last performance against Sergey Pavlovich in his UFC debut.

Overeem vs. Oleinik will now headline the second UFC card from Russia and first event held in Saint Petersberg.