ROBERT HELENIUS failed a drug test before he fought Anthony Joshua.
Matchroom Boxing boxing confirmed the shock news with a statement on social media.
It comes after AJ's original opponent Dillian Whyte also failed a drugs test and was forced out of the fight.
In the statement, Matchroom said that Helenius, 39, returned an "adverse analytical finding" during his test.
It continued: "Today, the Voluntary Anti-Doping Association (Vada) had informed Matchroom and the British Boxing Board of Control that Robert Helenius has returned an adverse analytical finding as part of a random anti-doping protocol.
Putin accused of surrounding himself with same 'actors' at series of events
"Helenius was voluntarily tested on Friday, 11 August before the heavyweight fighter's defeat by Anthony Joshua in London on Saturday, 12 August.
"The result was made known to Matchroom today.
"Matchroom defer to the relevant regulatory authorities on next steps.
"We vehemently continue to support voluntary anti-doping testing.
"We are committed to promoting a clean and fair sport for all athletes.
"We will not be making any further comment."
BETTING SPECIAL - BEST NO DEPOSIT CASINO OFFERS
Helenius was beaten in the fight by AJ after a brutal knockout punch in the seventh round.
However, Joshua, 33, had to work for the win and he was booed for his laboured approach.
The Finn stepped in last minute to replace Whyte after the boxer, who had been scheduled to take on rival Joshua, also failed a drug test.
Edinburgh Hogmanay revellers stuck in queues for TWO HOURS in torrential rain
Joshua praised Helenius after the fight as he claimed that he had "saved the show" and gave him a round of applause.
Joshua could next face Deontay Wilder in January if a deal can be agreed with the fight set to happen in Saudi Arabia.