Dustin Johnson
PGA Tour insists that Dustin Johnson's absence is voluntary.Jim Rogash/Getty Images Sport

The PGA Tour have insisted Dustin Johnson has not been suspended following his decision to take a break from golf for personal reasons.

Johnson, 30, announced on Thursday he was stepping away from the game in order to "seek professional help for personal challenges", sparking speculation the American had been sanctioned by the leading organiser of professional golf in the United States.

Golf.com reported Johnson had been hit with a six month suspension after testing positive for cocaine, but the Tour insist his absence is voluntary.

A statement read: "With regard to media reports that Dustin Johnson has been suspended by the PGA Tour, this is to clarify that Mr Johnson has taken a voluntary leave of absence and is not under any suspension from the PGA Tour."

Johnson's decision will see him miss the final major of the season in next week's PGA Championship at Valhalla and also rules him out of contention of the Ryder Cup at Gleneagles next month.

He said in his original statement: "By committing the time and resources necessary to improve my mental health, physical well-being and emotional foundation, I am confident that I will be better equipped to fulfil my potential.

"I respectfully ask my fans, well-wishers and the media for privacy as I embark upon this mission of self-improvement."

Johnson was the only member of the United States' Ryder Cup team to remain unbeaten when Europe triumphed two years ago, and his decision comes as a blow to team captain Tom Watson's plans ahead of the announcement of his 12-man team.

"We will certainly miss Dustin Johnson at Gleneagles, and we wish him the best," Watson said.

"As one of the longest hitters in the game with an undefeated record of 3-0 at Medinah in 2012, he has clearly been an asset for the United States team."