Tim Tszyu had to change up his preparations for his upcoming fight last week when original opponent Keith Thurman dropped out due to injury.
The pair were set to meet March 30, but Thurman's exit allowed for Sebastian Fundora to step in on less than two weeks' notice.
Fundora was scheduled to fight on the undercard, but will instead challenge Tszyu for his WBO super welterweight title and the vacant WBC title in the main event.
Changing opponents on such short notice can throw preparations off, but this may be especially true for Tszyu, who must now adjust to facing a fighter nearly a foot taller than Thurman.
Tszyu brought in a taller sparring partner to account for the height difference but admitted that the change is a big one to deal with on so little time.
“I had sparring for the new opponent come in on Monday and I was grateful for the great work they gave me," Tszyu said at a media workout on Thursday.
"This fight is all about awkwardness when you have someone that tall. But nothing fazes me. It is what it is and the show goes on.
“This is a unification now, so I’m very grateful for that. It’s a legacy-defining type of fight. I just have to keep doing what I’m doing and one day they’ll say that the Tszyu family is the best to ever step into this boxing world."
Live on DAZN: Watch Dalton Smith vs. Jose Zepeda on March 23