The PGA Tour has refuted a report that Dustin Johnson has been suspended.

Johnson said in a vague statement issued by his management company that he would take a leave of absence effective immediately to seek professional help for 'personal challenges'.

The announcement brought an abrupt end to his PGA Tour season, knocking him out of the PGA Championship and the Ryder Cup.

A golf website reported that the tour suspended Johnson for six months, citing an unidentified source as saying Johnson failed a drug test for the third time.

"With regards 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 a suspension from the PGA Tour,'' the tour's statement said.

It is rare for the tour to comment on any matters related to potential discipline.

PGA drug testing

The PGA Tour began drug testing in July 2008.

One year later, PGA Tour Commissioner Tim Finchem was asked to confirm that there had been no positive tests in the first year from either recreational or performance-enhancing drugs.

"I said we have had no positive tests with respect to performance enhancing. We may have had some test results that trouble us in other areas that we treat in a different bucket,'' Finchem said in July 2009.

"But we don't publicise those. We treat those as conduct unbecoming. If we get a test like that, we will consider it conduct becoming, and what are our choices? We can suspend a player. We can fine a player. We can do both of those and put a player into treatment.''

Johnson is not the first player to take a leave of absence. 

John Daly announced in September 1994 that he was taking the rest of the year off because of 'mental and physical' problems.

In announcing Daly's decision, Finchem repeatedly used the word 'voluntary', but said the decision was reached after numerous meetings between Daly and the tour.

Source: AP