Anthony Joshua’s American debut is in jeopardy after opponent Jarrell ‘Big Baby’ Miller was reported to have failed a drugs test.

Joshua was scheduled to fight Miller at New York’s Madison Square Garden on June 1 but it emerged on Wednesday that Miller had tested positive on March 20 for muscle growth substance GW1516 and on Wednesday night it is believed that the New York State Athletic Commission denied his application for a licence. 

The revelation of a negative finding for performance enhancing drugs on March 20 almost certainly leaves promoter Eddie Hearn scrambling to find a replacement.

Anthony Joshua’s opponent Jarrell ‘Big Baby’ Miller failed a drugs test, it has been reported

The heavyweight clash was set to be Joshua’s debut in the United States but it is now in doubt

Hearn tweeted: ‘We have been informed by VADA that there has been an adverse finding in Jarrell Miller’s sample collected on March 20th, 2019. 

‘We are working with all relevant parties and will update with more details soon. AJ’s preparation continues for June 1st at MSG.’

A statement from Miller’s camp said: ‘We are in the process of obtaining further information about VADA’s finding and will have more to say soon on this developing situation. 

‘In the meantime Jarrell continues to train for his June 1 fight against Anthony Joshua. 

ESPN, citing three people with knowledge of the situation, said 30-year-old Miller tested positive for banned muscle growth substance GW1516. A second sample may now be tested. 

Joshua’s promoter Eddie Hearn now faces the real prospect of finding a late replacement

Hearn took to social media in the early hours of Wednesday to clarify the Miller situation

The substance was added to the World Anti-Doping Agency’s banned list in 2009. 

The saving grace for the Joshua camp is that there is still six weeks to go, which should allow time to find another heavyweight.

Hearn has a stable of British heavyweights but the difficulty would be finding an American to take over good enough to attract a big crowd in New York and the television sales.

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WHAT IS GW1516?

GW1516 was developed in the 1990s as a treatment for diabetes, obesity and cardiovascular disease. 

It works by forcing skeletal muscle to use fat rather than carbohydrates as an energy source. 

While it is used by some to accelerate fat loss, it also has real benefits as an endurance aid for athletes.  

One option could be a rematch with Joseph Parker, who Joshua beat on points in Cardiff last March to claim the WBO belt.

New Zealand fighter Parker, in dialogue with fans on Twitter after news emerged about Miller, insisted he is ‘very ready and willing’ to take the fight on with just six weeks to go.  

Before Tuesday night’s news, the fight had broken sales records for the iconic New York venue, taking just two hours to become the highest-grossing pre-sale there ever.

Watford-born former Olympian Joshua is due to have his WBA, WBO and IBF heavyweight titles on the line in the bout. 

In the build-up to the fight it was Miller who alleged that Joshua was ‘not clean’ as he questioned the physique of the British boxer.

‘Nobody could have put on 20-pounds between winning the Olympics and his first pro fight the way Joshua did without taking something. Impossible,’ Miller said during the press tour.   

Sarah Fina, vice president of Miller's promotional company, gave a brief statement on Twitter

Sarah Fina, vice president of Miller’s promotional company, gave a brief statement on Twitter

Joseph Parker, who Joshua beat on points in Cardiff in March 2018, is interested in the fight

Joseph Parker, who Joshua beat on points in Cardiff in March 2018, is interested in the fight

‘We’ve busted our b**** to get full testing for 10 weeks to make sure he’s clean before June 1. We’ve covered the bases. 

‘If he’s been taking performance-enhancing drugs I couldn’t care less now. I’ve studied him. His physique, his power, his stamina.’

With Tyson Fury and Deontay Wilder already preparing for bouts of there own, Hearn and Joshua’s team face a tough ask to secure a fighter with a reputation good enough to step into the ring at the famous Madison Square Garden. 

Fellow Briton Dillian Whyte looked set to face Joshua at Wembley Stadium before the Miller fight was secured but a deal was unable to be agreed between the two teams.

On Wednesday, Hearn confirmed that Luis Ortiz is the first choice to replace Miller, saying: ‘I love that fight and AJ says he will fight anyone.’ 

After news broke about Miller, the New Zealander took to Twitter to throw his hat into the ring

After news broke about Miller, the New Zealander took to Twitter to throw his hat into the ring

During an explosive press tour it was Miller (pictured) who questioned Joshua and his physique

During an explosive press tour it was Miller (pictured) who questioned Joshua and his physique