Oscar De La Hoya confirmed he was in hospital receiving therapy after testing optimistic for coronavirus.
The boxing legend was due to come out of retirement to face former UFC champion Vitor Belfort on September 11.
That bout will now not be occurring, with TMZ first reporting that De La Hoya had contracted COVID.
The 48-year-old subsequently confirmed the news on social media and posted a video from his hospital mattress.
He wrote: “Wanted you to hear instantly from me that regardless of being totally vaccinated, I’ve contracted Covid and am not going to have the option to fight subsequent weekend.
“Preparing for this comeback has been the whole lot to me during the last months, & I need to thank everybody for his or her great help.
“I am currently in the hospital getting treatment and am confident I will be back in the ring before the year is up. God bless everyone and stay safe.”
There is a contingency plan for the deliberate card from Triller on September 11.
TMZ report that Evander Holyfield may step in as De La Hoya’s substitute.
The occasion may be moved from Los Angeles to Florida if the California State Athletic Commission is unwilling to licence the 58-year-old former world heavyweight champion.