Jarrell Miller: Anthony Joshua left chasing solutions says Mike Costello and Steve Bunce
Unified world heavyweight champion Anthony Joshua risks his US debut being tarnished by the stigma of a "substitute" opponent as a result of the "rank stupidity" of Jarrell Miller.
That is the view of BBC Radio 5 Live boxing's team, while others in the sport have called for Miller's failed drug test to lead to a lifetime ban.
Miller, 30, said he has "never knowingly taken any banned substance" but his chance to challenge Joshua at New York's Madison Square Garden on 1 June looks almost certainly gone, after he was denied a licence to fight.
Here, BBC Sport commentator Mike Costello and boxing analyst Steve Bunce question what happens next? What does this mean for Joshua? And who will now stand across the ring from him when he makes his US debut?
Procedure unlikely to save Miller
Miller was tested on 20 March but a substance known as GW501516 - often referred to as Cardarine or Endurobol - was found in his A sample. Both the fighter and his team now want his B sample tested and will contest the New York State Athletic Commission's decision to refuse him a licence if they can prove the findings are an error.
The New York-based fighter previously failed a test when competing as a kickboxer in 2014, resulting in a nine-month ban from the California State Athletic Commission.
Costello said: "The substance is known to boost energy and have cardiovascular effects for an athlete. It became known to the authorities around the time of the Beijing Olympics in 2008. During the Games it became known that many athletes were using it and so it was added to the banned list.
"Great credit should be given here to the Voluntary Anti-Doping Association, the organisation enlisted by many big promoters these days on the urgings of their fighters to conduct testing throughout camps. In the past three years they have caught Tyson Fury, Billy Joe Saunders, Saul 'Canelo' Alvarez and a long list of boxers, including Miller.
"Boxers are tested for blood and urine, in this case it's urine. Tests are placed in two separate vials - the A sample and B sample. They test the A sample first without ever opening the B. Then the athlete is notified if there is an adverse finding. They now have the opportunity to watch the second sample being tested.
"Miller can take along any representative he likes to watch but it is highly unusual for the second sample to produce different results to the first.
"It then comes down to how strong the authorities want to be in terms of their punishment. We are saying the fight is in jeopardy rather than off but I'd be pretty certain the fight is off."
Lifetime bans and swift action
Miller stands to miss out on about £5m in earnings as a result of the findings but is adamant he will not "lie down and let my dream be taken away from me".
Dave Coldwell - former trainer of Tony Bellew and currently overseeing Dereck Chisora - reacted to news of Miller's test by stating he "has to be kicked into touch without a doubt".
In an interview conducted with IFL TV, hall-of-fame trainer Freddie Roach said failed tests should see fighters "banned for life".
Roach, who has trained the likes of Manny Pacquiao and Miguel Cotto, says a risk of "attempted murder" exists if a fighter is using performance enhancing substances, adding that punishments are not adequate to deter use.
"The rule isn't strong enough where guys will try to do it," said Roach. "I think you should be gone from boxing forever."
The New York State Athletic Commission moved quickly in stating Miller would not be granted a licence.
Costello was unsurprised by the swift action from a commission which agreed to a $22m (£18.7m) payout to injured fighter Magomed Abdusalamov in 2017 as a result of medical malpractice after a bout which left the Russian unable to walk.
"Since then, every promoter who has put on a show anywhere in New York has to put up $1m [£770,000] insurance or have a premium that will cover $1m of medical care for any boxer who suffers a traumatic brain injury," adds Costello.
"With that kind of background, can you imagine those authorities letting Miller get into a ring?
"What happens if Miller inflicted injury on Joshua?"
Substitutes and disasters
Unless Miller's B sample returns clean, IBF, WBA and WBO champion Joshua will now require a new opponent for a date and venue his team are adamant will remain in place.
The Madison Square Garden bout was seen as his route to break into the American market and as an effective use of his next fight, given negotiations with the division's two other stand-out names - Deontay Wilder and Tyson Fury - broke down.
The fight night is worth a reported $25m (£19.21m) to the Briton and is a key fixture in the calendar of streaming service DAZN - the platform on which he fights in the US.
There is also the issue of Joshua having already been out of the ring since his win over Alexander Povetkin - who has also tested positive for banned substances - in September, meaning any delays to his next contest will extend a sizeable period of inactivity.
"Miller has made himself look an idiot and discredited the sport," said Frank Warren, who promotes Tyson Fury in the UK.
"The good thing they have now is time to find an opponent. Had it happened a week before the fight they'd have been knackered.
"They have to come up with a name, an American, as DAZN will want something sellable. This for them was a fight to introduce him. It looks like it will go by the wayside unless they can find something special."
Joshua's promoter Eddie Hearn claims countless heavyweights have made contact wishing to fill the void, including Dereck Chisora's manager David Haye, who says they will seek a contest back in London if Chisora beats Senad Gashi on Saturday.
"The splintering of the ways with Fury, Wilder and others being signed with different TV networks has meant the number of quality opponents who should be in the corner on an occasion like this is diminishing," added Costello.
"We're looking at names like Adam Kownacki - with a record of 19 unbeaten. They've mentioned Luis Ortiz - who gave Wilder a headache for 10 rounds. Another name is Michael Hunter, who is at the lighter end of the division in terms of weight.
"One or two have put up the name Dillian Whyte. In this pay-per-view age, I just don't think there's enough time to build and stoke a fight like that.
"Whoever they bring in, the problem now is whoever comes in will be tarnished with the label of a substitute. Though we have seen substitutes cause mayhem in the past."
Bunce added: "There's been a shock and rank stupidity on behalf of Miller.
"We've been saying about Miller he can talk, he will sell the fight. Whether or not he is gone or not, the fight has lost its shine.
"When we left Los Angeles after Wilder v Fury in December we thought we had two fights set in stone. One was Joshua v Dillian Whyte, provided Whyte could beat Chisora which he did. The other one we were convinced on was a Wilder v Fury rematch. Both should have happened by May and then we'd have more by September.
"What a disaster recent months have been for the heavyweight division."