Devin Haney may be the undisputed lightweight champion, but he is not exactly undefeated, alleges upcoming adversary Regis Prograis.

Ahead of a press conference to announce their Dec. 2 junior welterweight title bout at Chase Center in San Francisco, Prograis put forward the notion that Haney had paid someone off to remove a loss from his record early on in his career, when Haney was gaining experience by fighting almost exclusively in Mexico for the first two years of his career. Haney, 24, turned professional in December of 2015, at age 17.

“So I’m hearing Devin lost a fight in Mexico earlier in his career but he paid to take it off his record,” Prograis wrote on X (formerly Twitter). “IF that’s true that’s the weakest sh!t I ever heard so far in boxing. Press conference is Tuesday and y’all reporters better not let this sh!t slide.”

Prograis followed up with another post, doubling down on his initial claim.

“Just got confirmation that it’s true,” Prograis wrote. “Y’all reporters better do y’all research.”

It did not take long for Haney to fire back at Prograis, saying the unverified rumor was concocted by WBA 140-pound titlist Rolando “Rolly” Romero.

“Only a dumbass would believe some sh!t like that..” Haney posted on X. “This info is coming from Rolly that should tell u enough.”

Haney, the former undisputed lightweight champion, is moving up to the 140-pound division for the first time in his career to face Prograis. The fight will double as a homecoming for Haney, who although a longtime and current resident of Las Vegas, was born in San Francisco.

Haney (30-0, 15 KOs) is coming off two successful defenses of his four lightweight belts, with wins over George Kambosos Jr. and Vasiliy Lomachenko.

The 34-year-old Prograis (29-1, 24 KOs), who won his WBC title with a stoppage win over Jose Zepeda last year, is coming off a relatively disappointing points win over Danielito Zorrilla in June.

Sean Nam is the author of Murder on Federal Street: Tyrone Everett, the Black Mafia, and the Last Golden Age of Philadelphia Boxing.