Mikaela Mayer will face a different opponent than she was scheduled to box Saturday night in London.

Christina Linardatou, the former IBF/WBO 130-pound champion’s original opponent, was not cleared for licensure Friday by the British Boxing Board of Control. BoxingScene.com has learned that the BBBofC wouldn’t approve Linardatou for a license based on the result of Linardatou’s pre-fight eye exam, which prevented her from weighing in for her 10-round fight against Mayer on the Joe Joyce-Zhang Zhilei undercard at Copper Box Arena.

Lucy Wildheart agreed to step in for Greece’s Linardatou on very short notice. She’ll meet Mayer for the WBC interim lightweight title in a co-feature BT Sport 1 will televise in the United Kingdom and Ireland (7 p.m. BST) and ESPN+ will stream in the United States (3 p.m. EDT; noon PDT).

The 32-year-old Mayer (17-1, 5 KOs), of Colorado Springs, Colorado, will make her debut at the lightweight limit of 135 pounds versus Wildheart (10-1, 4 KOs), a native of Sweden who resides and trains in England. The 30-year-old Wildheart has lost only a 10-round unanimous decision to France’s Estelle Mossely (11-0, 1 KO) in June 2019.

Wildheart has won five fights in a row since Mossely beat her, but she has beaten a low level of opposition in those bouts. The more formidable Linardatou (14-2, 6 KOs) has lost only a pair of 10-round unanimous decisions to undisputed lightweight champ Katie Taylor (22-0, 6 KOs) and Delfine Persoon (47-3, 19 KOs, 1 NC) in a pair of title fights.

Mayer, a 2016 U.S. Olympian, will fight for the first time since she lost to rival Alycia Baumgardner by split decision in their 10-round, 130-pound title unification fight October 15 at O2 Arena in London.

Mayer pushed for an immediate rematch with Baumgardner (14-1, 7 KOs), but Baumgardner instead fought France’s Elhem Mekhaled on February 4 at The Theater at Madison Square Garden in New York. Baumgardner beat Mekhaled (15-2, 3 KOs) by unanimous decision in their 10-round bout and retained her IBF, IBO, WBA, WBC and WBO 130-pound championships.

Once it became clear she wouldn’t get an immediate rematch with Baumgardner, Mayer moved up to the lightweight division to battle Linardatou, who is the only opponent who has beaten Baumgardner.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.