SAN ANTONIO – If Jermell Charlo beats Brian Castano on Saturday night and remains at 154 pounds, a rematch with Erickson Lubin will be inevitable unless Charlo decides to give up the WBC super welterweight title.

Nearly four years after Charlo knocked out Lubin with one punch in the first round, Lubin is the mandatory challenger for Charlo’s WBC championship again. Houston’s Charlo understandably believes he has nothing to prove by boxing Lubin again and would prefer to face other opponents if he conquers Castano.

“I actually have no interest in that fight,” Charlo told BoxingScene.com following a press conference Thursday at the Thompson San Antonio-Riverwalk hotel. “I don’t know. I have to see. If I’ve gotta fight my mandatories, then I’ll fight my mandatories. That’s what I did. That’s the reason why he got that position [for their first fight], was me facing my mandatories.

“But if I have to fight him, I will fight him. You know what I’m saying? Whatever my management tell me to do, I’ll get in there and fight any one of those guys because they all warriors.”

The left-handed Lubin was just 22 when he challenged Charlo in October 2017 at Barclays Center in Brooklyn. Charlo caught a vulnerable Lubin with a short right hand that sent Lubin to the canvas awkwardly with 28 seconds to go in the opening round of their scheduled 12-round bout.

Lubin struggled while attempting to get up from that staggering shot, so much that referee Harvey Dock waved an end to their title fight just 2:41 after the opening bell rang.

The 25-year-old Lubin has won each of his six fights since Charlo knocked him out, including a sixth-round stoppage of former IBF/IBO/WBA champion Jeison Rosario last month. Orlando’s Lubin (24-1, 17 KOs) knocked Rosario to the canvas twice during the sixth round before their scheduled 12-round WBC elimination match was stopped June 26 at State Farm Arena in Atlanta.

The 31-year-old Charlo wasn’t overly impressed by Lubin’s win because the IBF/WBA/WBC champion feels he softened up Rosario in Rosario’s previous fight. Charlo floored Rosario (20-3-1, 14 KOs) once apiece in the first, sixth and eighth rounds and knocked out the Dominican contender with a body shot during the eighth round September 26 at Mohegan Sun Arena in Uncasville, Connecticut.

“Man, I did all that damage to Rosario, so I don’t care about it,” Charlo said in reference to Lubin’s win. “I didn’t really look at it like that. He need to fight somebody that’s much tougher. I exposed Rosario, basically, and now they think that they did something? If Lubin wanted to prove something, he should’ve tried to prove it against one of those top-tier guys like [Erislandy] Lara. Those are the type of matchups I have faced. I faced tough matchups my whole career.”

Showtime will televise the 12-round, 154-pound title unification fight between Charlo (34-1, 18 KOs) and Argentina’s Castano (17-0-1, 12 KOs) as the main event of a three-bout broadcast from AT&T Center. They’ll fight for Charlo’s three titles and Castano’s WBO belt as part of a telecast set to start at 9 p.m. ET.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.