Nate Schmidt has been banned for the first 20 games of the National Hockey League (NHL) season for a doping offence.
The American, a defenseman for Vegas Golden Knights, was found to have "violated the terms of the NHL/NHLPA Performance Enhancing Substances Programme".
He will not be paid during the suspension period and will be referred to the NHL programme for substance abuse.
No details on what he failed for or when have been released but the 27-year-old moved to defend himself in a statement.
He claimed that only a "microscopic" amount of a prohibited substance was found in his system and said he had not bent the rules deliberately.
"I am extremely disappointed to learn that I have been suspended for a violation of the NHL/ NHLPA Performance Enhancing Substances Programme," Schmidt said.
"The fact that I'm issuing this statement is surreal to me as I have only used supplements provided by my NHL team and I have always been extremely careful about what I put into my body.
"Throughout my playing career I have been tested numerous times, including twice last season, and I have never before tested positive.
"It was utterly shocking to be informed that I tested positive for a microscopic amount of a tainted substance.
"Not only did I not intentionally take a banned substance, I could not have received any performance enhancement benefit from the trace amount that inadvertently got into my system at a level that was far too small to have any effect.
"This low amount was consistent with environmental contamination that I could not possibly have prevented.
"While I support having a strong Performance Enhancing Substances Programme in place for our sport, it is difficult to accept this suspension.
"I understand that I will miss these games, but I do not agree with the suspension and I will not accept being labelled a cheater."
Schmidt will be able to return against Edmonton Oilers on November 18.
He played for the Las Vegas side in their inaugural season last term when they incredibly reached the Stanley Cup Finals before defeat to Washington Capitals.
"We were notified that the NHL has suspended Nate Schmidt for violating the terms of the NHL/NHLPA Performance Enhancing Substances Programme," the Golden Knights said in a statement.
"While we respect the NHL/NHLPA Performance Enhancing Substances Programme, we strongly dispute the suspension.
"We firmly believe that the presence of a trace of the banned substance was accidental and unintentional.
"Based on our conversations with Nate, analysis from independent medical experts and sworn testimony from the parties involved, we believe it is clear Nate was not able to reasonably ascertain how the substance entered his body.
"Nate is an honest person with high moral character and great integrity.
"We will stand by him and support him during this time."