SAN JOSE, Calif. (AP) — Matt Mitrione was hospitalized with a kidney stone Saturday, forcing the cancellation of his fight against heavyweight Fedor Emelianenko in the main event of Bellator 172.

Mitrione took part in the pre-fight activities throughout the week despite being in discomfort. The pain worsened following Friday's weigh-in and continued overnight. Mitrione was eventually sent to a local hospital where doctors discovered the kidney stone.

Bellator President Scott Coker said discussions about a possible replacement for Mitrione were held but because of time constraints and other concerns, the decision was made to cancel only hours before the scheduled three-round bout.

"This morning (Mitrione) was in excruciating pain," Coker said. "We're not going to put Matt in any kid of situation where he's in harm's way."

Flyers announcing the cancellation were taped to poles in the parking lots and fans were offered full refunds, though few seemed to do that.

Coker hopes to reschedule the fight for later this year, possibly in May or June, at the SAP Center where the original fight was to be held.

"We just have to wait and see if Matt is going to be OK to do it," Coker said. "If not, we'll find Fedor another opponent."

Emelianenko, the 40-year-old Russian who once crafted a winning streak that spanned nearly a decade, is widely recognized as one of the greatest heavyweights in the MMA history and was scheduled to fight in the United States in more than five years. The fight against Mitrione, a former UFC contender, was to be Emelianenko's first in Bellator.

"It's disappointing," Coker said. "We all came here to see Fedor fight in the main event. I feel bad for him because the guy's in tip-top shape, ready to go, ready to fight, came here to fight and there's no fight."

Instead of fighting, Emelianenko worked the corner for Anatoly Tokov who beat Francisco France on the undercard. Tokov is a member of Emelianenko's team.

Afterward, Emelianenko spoke to the crowd from the ring through an interpreter and expressed his disappointment.

"We were preparing for this fight really very hard," Emelianenko said.

The rest of the card went on as planned.

Former UFC welterweight contender Josh Koscheck was stopped in the first round of his Bellator debut by Brazillian Mauricio Alonso. Alonso landed a right uppercut that staggered Koscheck and later knocked him to the mat before referee John McCarthy stepped in.