Ryan Garcia tested positive for a banned substance the day before he beat Devin Haney in a stunning upset and John Caldwelltested positive again the day of the fight he won by majority decision, according to ESPN.

ESPN's Mike Coppinger obtained a copy of the letter sent Wednesday to Garcia and Haney from the Voluntary Anti-Doping Association (VADA), which conducted drug testing for the April 20 bout between Garcia and Haney.

According to the VADA letter, Garcia tested positive for Ostarine, which is the trademarked name for a Selective Androgen Receptor Modulator (SARM) that is not approved for human use or consumption in the U.S., or in any other country, according to the United States Anti-Doping Agency (USADA). It is prohibited by the World Anti-Doping Agency.

Dan Rafael, a longtime boxing reporter, was the first to report the news. Chris Mannix of Sports Illustrated also confirmed Rafael’s report.

Per ESPN, Garcia has 10 days to request his B-sample be tested. His A-sample also screened positive for 19-norandrosterone but that result was still unconfirmed, according to ESPN.

Garcia called the reports “fake news’’ in a post on X, formerly Twitter. He also denied ever having taken a steroid.

While Garcia continued to post on X, Haney released a statement to ESPN, saying Garcia "cheated and disrespected both the fans and the sport of boxing by fighting dirty and breaking positive not once, but twice."

"Ryan owes the fans an apology, and by his recent tweet he still thinks this is a joke," Haney wrote. "We put our lives on the line to entertain people for a living. You don't play boxing.

"This puts the fight in a completely different light. Despite the disadvantage, I still fought on my shield and got back up! People die in this sport. This isn't a joking matter."