LAS VEGAS -- Sonny Conto will have to wait a little longer to end his already lengthy layoff.

The unbeaten heavyweight prospect from Philadelphia is left without an opponent, as Phoenix’s Waldo Cortes was dropped from the show due to undisclosed medical reasons, has learned. The development occurred Saturday morning, not leaving any time to secure a replacement opponent for Conto who has not fought since last January.

The bout was to have aired on the ESPN+ undercard portion of Saturday’s highly anticipated junior lightweight title clash between defending WBC champ Miguel Berchelt (38-1, 34KOs) and Oscar Valdez (28-0, 22KOs). The main event remains intact, topping a seven-fight card from MGM Grand Conference Center in Las Vegas.

Cortes (6-3, 3KOs) was due to make his second MGM Bubble appearance, ironically to have come versus Conto last June 25. Conto was forced to drop off the show and was replaced by Kingsley Ibeh, who stopped Cortes inside of four rounds to avenge a points loss from eight months prior.

Cortes rebounded with a 1st round knockout in Scottsdale, Arizona last October and weighed 255 ½ pounds at Friday’s official weigh-in for his intended showdown with Conto. It proved to be moot, as the heavyweight and his team were forced to leave the MGM bubble Saturday morning.

All of this leaves Conto (6-0, 5KOs) as an unfortunate casualty.

The charismatic 25-year old prospect has been out of the ring since a 1st round knockout of Curtis Head last January in Atlantic City. Conto gained greater acclaim in joining the training camp of England’s Tyson Fury (30-0-1, 21KOs) ahead of his heavyweight championship rematch with Deontay Wilder (42-1-1, 41KOs).

Efforts to cash in on the profile boost have thus far proven futile. Conto was due to make his Bubble debut last June, only to have to withdraw from the show and ultimately kept out of the ring for the remainder of 2020.

Conto-Cortes becomes the second undercard bout to be pulled from the show in the last 24 hours. A battle of unbeaten junior lightweight prospects between Bryan Lua and Frevian Gonzalez was removed from the card on Friday after Lua also tested positive for COVID-19.

Five fights remain on the undercard portion of the card, airing live on ESPN+ at the modified start time of 6:45 p.m. ET/3:45 p.m. PT.

Jake Donovan is a senior writer for Twitter: @JakeNDaBox