De la Hoya had been training for a comeback against martial-arts fighter Vitor Belfort after more than a decade away from the ring, in a fight he hoped could bring closure to his career.
Instead, the 48-year-old former champion ended up hospitalized for three days with a COVID-19 infection even though he said he had been vaccinated.
He's now out of the hospital.
"COVID hit me really hard," de la Hoya said in a video posted Wednesday. "I was in the best shape of my life and I really can't wait to get back in the ring. Thank you very much for all your well wishes and all your support. I appreciate it."
De la Hoya withdraws from fight after COVID-19 infection
Oscar de la Hoya withdraws from comeback bout as he fights COVID-19 infection
The de la Hoya-Belfort fight had been scheduled for this Saturday at Staples Center.
Instead, former heavyweight champion Evander Holyfield, 58, will fight Belfort in Florida, after the California Athletic Commission refused to approve the fight because of his age.
Former President Donald Trump and his son Donald Jr. will provide ringside commentary for the Holyfield-Belfort exhibition match.
Donald Trump to provide ringside commentary on Holyfield fight on Sept. 11
Trump and Donald Jr. to provide commentary on Holyfield fight in Florida on Sept. 11