Trainer Virgil Hunter said the substance was in a brown bottle resembling a Vaseline tub apparently hidden in a bag in Miranda's corner. When Miranda's cornermen were spotted taking the substance out of the bag around the fourth or fifth rounds of the fight at Oakland's Oracle Arena, it was seized before officials actually saw it given to Miranda, according to promoter Dan Goossen.
"We're not sure if anything was going on, but it's good they caught it," Hunter said.
Goossen said the athletic commission will test the substance and could have results by Monday.
The commission's offices were closed Sunday, but spokesman Luis Farias confirmed officials seized something from Miranda's corner during the bout. The commission will determine its next step Monday, Farias said.
Ward (19-0) won the 168-pound fight in his hometown with a comfortable unanimous decision over Miranda (32-4), a former top middleweight prospect who has lost to champions Arthur Abraham and Kelly Pavlik in the past two years.
"I don't want to jump to any conclusions right now," Goossen said. "That's why I didn't say anything (Saturday). There's nothing worse than taking away from a good victory by putting the focus on something else."
Miranda's managers, Steve Benbasat and Greg Wantman, didn't immediately respond to e-mails.
Hunter and Goossen don't assume anything illegal occurred, and most of the substances applied to boxers' heads and bodies during fights are legal petroleum jelly mixes or coagulants to stop bleeding.
But boxing lore also is filled with stories of substances surreptitiously applied to a fighter's head or arms that could irritate an opponent's eyes or open cuts. Ward had a cut above his eye from early in the first round after a head-butt from Miranda.
Petroleum jelly is routinely applied to fighters' faces to stop cuts and to lessen the impact of punches to the face, although it's not allowed on the body and can't be used excessively, according to California's boxing code of regulation.
The California commission suspended former welterweight champion Antonio Margarito for at least one year in February after illegal wraps containing a substance resembling plaster of Paris was discovered on his hands before his fight against Shane Mosley in Los Angeles.
Ward stated his case for a title shot with his decisive victory over Miranda, although the 2004 U.S. Olympic gold medalist might not get it immediately. Ward has called out WBC champion Carl Froch of Britain, and Goossen also would like to match Ward against IBF 168-pound champ Lucian Bute, who hasn't fought outside of Montreal in four years.
"I want any champion with a belt," Ward said. "My respect is here now, and it's going to continue to grow. That's the story of my career.... I don't know what it is about my style, but they get in there and then they see something different. By the time they figure it out, it's too late."