Day, 27, from Freeport, Long Island, was taken to Northwestern Memorial Hospital with a “traumatic brain injury,” according to DiBella Entertainment, his management team. He suffered seizures on the way and underwent emergency surgery, ESPN reported.

“Patrick’s condition is extremely grave,” Day’s trainer, Joe Higgins, told Newsday Sunday. “He is fighting for his life. That’s all we can really say right now.”

Day was an alternate on the 2012 Olympic team, ESPN noted.

He has a record of 17-4-1 with six victories coming by knockout. Saturday marked the second time he had lost by knockout.