Erik Morales, due to defend his version of the junior welterweight title against Danny Garcia on Jan. 28, underwent gallbladder surgery on Wednesday, leaving the bout in doubt.
Eric Gomez, matchmaker for Golden Boy, which promotes Morales, told ESPN.com that Morales had gallstones removed and that the procedure was minor.
However, he said it was unclear if the fight would take place.
"I spoke to (Morales). He asked us to please wait (until) Friday," Gomez said about the time frame for him to make a decision. Gomez said Morales would talk to his doctor before deciding what to do.
Morales (52-7, 36 KOs), the 35-year-old Mexican star and four-division titlist, is supposed to make his first defense against Garcia (22-0, 14 KOs) at Reliant Arena in Houston in the main event of the first HBO card of 2012.
Junior middleweight contenders James Kirkland and Carlos Molina are scheduled to meet in the televised co-feature.
Morales, who ended a 2½-year retirement in 2010, claimed a vacant 140-pound belt when he stopped late substitute Pablo Cesar Cano in the 10th round on Sept. 17 at the MGM Grand in Las Vegas on the Floyd Mayweather Jr.-Victor Ortiz undercard.
Garcia, 23, of Philadelphia, earned the shot with his best career victory, a decision against former titleholder Kendall Holt on Oct. 15 on the Bernard Hopkins-Chad Dawson undercard in the Staples Center in Los Angeles.
Dan Rafael covers boxing for ESPN.com. Follow him on Twitter.