11:57 AM PT -- De la Hoya just posted a video from his hospital bed. ODLH wrote ... "Wanted you to hear directly from me that despite being fully vaccinated, I have contracted Covid and am not going to be able to fight next weekend."
"Preparing for this comeback has been everything to me over the last months, and I want to thank everyone for their tremendous support. 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."
11:38 AM PT -- Our Oscar sources tell us the boxing legend -- despite being fully vaccinated -- has been hit hard by COVID ... and is receiving treatment in the hospital.
58-year-old Evander Holyfieldhas agreed to step in and box Belfort on September 11 on Triller, our sources tell us.
The one remaining hurdle is getting Holyfield-Belfort approved by the California State Athletic Commission.
If the commission does not sanction the match, we’re told the entire event will still go down ... but it’ll be moved to Florida.
The fight was supposed to be ODLH’s return to the ring after more than a decade ... after losing his last fight to Manny Pacquiao in 2008.
De La Hoya dedicated himself to getting back in peak physical condition in preparation for the fight over the last few months ... and looked to be in great shape, recently showing us his 6-pack as he left dinner in L.A.
As for Holyfield, The Real Deal -- one of the greatest fighters in boxing history -- last fought in 2011 ... but has recently talked about his desire to make a comeback to the ring.
Belfort -- an MMA legend -- has been more active over the last few years ... last fighting in the UFC in 2018.
The Anderson Silva vs Tito Ortiz fight is still a go.
Bottom line ... Oscar’s out, and Evander Holyfield and Vitor Belfort are fighting -- either in Cali or Florida.