By Gregory Stangrit, Alexey Sukachev

The card suffered a huge blow when the main event fell out earlier today. Deontay Wilder was scheduled to make a mandatory defense of his WBC heavyweight title against Alexander Povetkin.

The World Boxing Council officially postponed the fight after Povetkin failed a pre-fight drug test. The sanctioning body will now conduct an investigation.  

Ryabinsky is now re-shuffling the card, with a very tasty cruiserweight unification being moved up to the main event position.

Denis Lebedev (28-2, 21 KOs) and Victor Emilio Ramirez (22-2-1, 17 KOs) will collide in an IBF/WBA unification showdown.

Also on the card, up and coming Russian light heavyweight prospect Dmitry Bivol (6-0, 6 KOs) will have a chance to get a version of his first major belt, when he takes on Dominican Felix Valera (13-0, 12 KOs), who holds WBA Interim light heavyweight crown.

Another rapid bloomer Umar Salamov (15-0, 12 KOs), who is rated #9 by the WBO, will be pitted against experienced British fighter Bob Ajisafe (16-2, 7 KOs) in the toughest fight of his career so far.

WBC #10 rated 200lber Dmitry Kudryashov was 18-0, 18 KOs, when he ran into relatively undistinguished Nigerian Olanrewaju Durodola last November, and the terror of the division suffered a bitter setback, being blitzed in two. After somewhat intensive training sessions in the States Kudryashov is getting back against Brazilian veteran Julio Cesar Dos Santos (30-5, 27 KOs) in a scheduled ten-rounder.

Former IBO and EBU champion Rakhim Chakhkiev (24-2, 18 KOs) is also getting back. On the same card, where Kudryashov was stopped standing by Durodola, Chakhkiev lost his title to another Nigerian Ola Afolabi on a brutal kayo, his second career. Now WBC #14 Chakhkiev will see action over ten rounds against Tamas Lod (18-6).

WBA #10 and WBC #13 super middleweight Dilmurod Satybaldiev (10-1, 2 KOs) will risk his WBA Continental title for the second time, while WBA #4 super middleweight Stas Kashtanov (34-2, 20 KOs) will be featured in a non-title eight-rounder.

Rounding up the card are cruiserweight Alexey Papin (2-0, 2 KOs) and former female amateur superstar Sofya Ochigava, who will make her pro debut. Papin will see action over eight rounds against Yuri Bykhovtsev (9-8-2, 5 KOs) of Belarus. Former two-time world and three-time European amateur champion Ochigava, who also holds a silver medal of 2012 London Olympics, will be showcased in a four-rounder against Firuza Sharipova.

Gregory Stangrit covers boxing for Allboxing.ru.