The 33-year-old, poised to defend his WBA interim light heavyweight title against Britain's Lerrone Richards, has been forced to withdraw from their main event billing after falling ill and being hospitalized on Tuesday.

As such, an intriguing 175-pound battle between unbeaten contenders Mehmet Unal (14-0, 12 KOs) and European beltholder Altin Zogaj (17-0, 9 KOs) has been elevated to the headline slot on an Eye of the Tiger show taking place as planned from Canada's Montreal Casino on Thursday night.

In a press release, Ramirez was said to have had a 'flawless' training camp and remained injury-free. He attended the press conference without issue, though his condition has since worsened and while still being evaluated by doctors, is unable to compete.

On the news, promoter Camille Estephan described it as a 'heartbreaking decision' but one that needed to be made.

"Albert was absolutely determined to fight despite everything. However, it is our responsibility as promoters to protect the health of oura thletes, which is why this was the decision that had to be made."

London southpaw Richards (19-1, 4 KOs) returned with a six-round points win over journeyman Dylan Courtney last September, after a 15-month layoff following an upset stoppage loss by Steed Woodall at super middleweight.

Invited to spar highly-regarded contender Imam Khataev (11-1, 10 KOs) before his three-round blowout of Adam Deines on December 11, the 33-year-old made an impression and was then offered an opportunity to face Ramirez - much different than his distinct lack of luck in the months prior. Now, he'll be crossing his fingers again.