Another sample given, another failed drug test for Sergey Kovalev.

BoxingScene.com has learned that the former three-time light heavyweight world titlist has tested positive again for synthetic testosterone, failing a second random Voluntary Anti-Doping Association-administered drug test eight days after he also failed for the same banned substance that led to the cancelation of his 178-pound catch weight fight against up-and-comer Bektemir “Bek Bully” Melikuziev. The fight was scheduled to take place as the main event of a DAZN card on Jan. 30 at the Fantasy Springs Resort Casino in Indio, California.

For the first failed test, Kovalev supplied a sample to VADA on Dec. 30 in Las Vegas, which came back positive for synthetic testosterone on Jan. 13.

He was tested again on Jan. 7 in Oxnard, California, and that test returned a positive result on Friday, according to documentation obtained by BoxingScene.

“Adverse analytical finding: IRMS (isotope-ratio mass spectrometry) results are consistent with exogenous origin of testosterone and metabolites,” according to the letter VADA sent outlining the details of the test results to those involved in the now-canceled event, a copy of which was obtained by BoxingScene.

Kovalev (34-4-1, 29 KOs), 37, a Russia native fighting out of Santa Monica, California, was trying to make a comeback following the loss of the WBO 175-pound world title to Canelo Alvarez by brutal 11th-round knockout on Nov. 2, 2019 at the MGM Grand in Las Vegas. Alvarez had moved up two weight classes to challenge Kovalev for the title.

With another failed test, advancing age, eroding skills and a variety of issues outside the ring, it Kovalev’s future in boxing is cloudy. It also remains to be seen what kind of punishment the California State Athletic Commission will hand out following the positive drug tests.

But it seems unlikely that Kovalev will fight any time soon for what was supposed to be a $2.5 million comeback fight that was owed to him as part of the deal for the fight against Alvarez.

Kovalev was initially scheduled to fight former light heavyweight world title challenger Sullivan Barrera at 180 pounds in his comeback fight in the main event of a DAZN card on April 25, also at Fantasy Springs Resort Casino. However, that card was scrapped due to the coronavirus pandemic.

After the first failed test, Main Events CEO Kathy Duva, Kovalev’s longtime promoter, acknowledged the initial test result.

“We are aware of the adverse finding from VADA,” Duva said at the time. “Sergey Kovalev has been proven to be a clean fighter throughout the many years that he has been tested by VADA. VADA was contracted for this fight at his insistence, as he has requested for almost all of his fights going back several years. He maintains that he did not purposefully ingest any banned substances. We have made arrangements to have his supplements tested for contamination and will request that VADA test his B sample.”

Kovalev also has the right to have the B sample from Jan. 7 tested at his own cost.

Once the Jan. 30 card was canceled, Golden Boy Promotions, Melikuziev’s promoter, added him to the undercard of its Feb. 13 DAZN event at the Fantasy Springs Resort Casino. That card is headlined by junior lightweight titlist Joseph Diaz Jr. facing mandatory challenger Shavkatdzhon Rakhimov with junior middleweight titlist Patrick Teixeira making his first title defense against mandatory challenger Brian Castano in the co-feature.

Melikuziev (6-0, 5 KOs), 24, a 2016 Olympic silver medalist from Uzbekistan, will face an opponent to be determined in a 10-round super middleweight bout.

Dan Rafael was ESPN.com's senior boxing writer for fifteen years, and covered the sport for five years at USA Today. He was the 2013 BWAA Nat Fleischer Award winner for excellence in boxing journalism.