Miller recorded a positive sample for the banned muscle growth substance GW1516, leaving the New York State Athletic Commission to refuse him permission to fight Joshua at Madison Square Garden on June 1.
The 30-year-old could appeal dependent on results of a second sample or try to prove the test result, carried out by the Voluntary Anti-Doping Association, is flawed. But it is unlikely after the commission made clear their determination to crack down on the American.
Promoter Hearn insisted: “The testing is too sporadic in the US. There is simply not enough of it carried out.
“If the test taken by Miller was applied across America, so many fighters would be failing. Anthony insists on VADA testing for himself and his opponents from 14 weeks out from a fight and the cost comes out of the promotional budget.
“But there are boxers over there who go ages and ages without seeing anybody. It has to change.”
The NYSAC statement said: “The commission has denied Jarrell Miller’s professional boxing licence application for a violation relating to the use of a prohibited substance. We have no further comment at this time.”
Miller issued a statement, saying: “I am absolutely devastated and I will be vigorously appealing this decision.
“I have never knowingly taken any banned substance. My team and I stand for integrity, decency and honesty and together we will stand to fight this.”
The two leading boxing authorities are trying to improve drug testing, with the WBC and WBA teaming up with VADA to attempt to create a more stringent regime for a sport increasingly plagued by performance-enhancing drugs. The WBC have a clean boxing programme under which they insist all belt holders and those rated in their top 15 have to enrol or lose their ranking. And the WBA have a fair boxing programme which runs along similar lines.
Hearn, meanwhile, is adamant Joshua’s debut in the United States will go ahead and he has a list of stand-in opponents, including Luis Ortiz, Adam Kownacki, Kubrat Pulev, Mahmoud Charr and Michael Hunter.
Joshua is looking to defend his four world titles — the WBA, IBF, WBO and IBO — at Madison Sqaure Garden.