Hull manager Steve Bruce admits he is "shocked, saddened, disappointed and angry" after midfielder Jake Livermore tested positive for cocaine.
Livermore, who has been suspended by the Football Association and his club, missed Hull's 2-0 defeat to Tottenham on Saturday and could face a ban of up to two years.
Bruce said he broke the news of the failed test to Livermore on Wednesday in what he says was the hardest conversation he has ever had in his football career.
"I'm shocked, saddened, disappointed, angry - all of those things," Bruce said.
"Why wouldn't I be? I can't come to terms with it if I'm being honest but society today is unfortunately like that. The conversation I had with him is the hardest conversation I've ever had with any footballer.
"Informing him that he's failed a drugs test is not easy. He couldn't concentrate on anything really so it didn't really matter what I said. He's obviously in a dark place and we'll see what the outcome is from the FA and how they respond to it."
Hull paid £8million to sign Livermore from Tottenham last summer and the 25-year-old has made 39 appearances for the club this season.
Livermore's absence also comes as blow to Hull's chances of Barclays Premier League survival.
The defeat to Spurs left Bruce's side two points adrift of safety with one match remaining.
"We're all let down, from everyone concerned with the club and everyone concerned with football too," Bruce said.
"The biggest thing he's let down is a blossoming career, he's let himself down. To be tarnished with that is awful and he'll have to live with the consequences of that. Jake has taken a B-sample and then you'll have to ask Jake's lawyers.
"I believe he has to put his actions in writing before Thursday and then I think the hearing will be whenever it sits. It's not for me to be judge and jury but I'm obviously disappointed with the whole thing."
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