Rory McIlroy believes the PGA Tour were right to clear Vijay Singh of a doping offence and insists he will be happy to undergo the type of out-of-competition testing experienced by his girlfriend Caroline Wozniacki.

Singh admitted in January to using deer antler spray, which contains small amounts of IGF-1 (Insulin-like Growth Factor-1), a growth hormone on the World Anti-Doping Agency (Wada) and PGA Tour list of prohibited substances.

The three-time Major winner told Sports Illustrated he used the spray “every couple of hours...every day” and was “looking forward to some change in my body.”

Although he had not failed a test — and no test even exists — that was treated as a violation of the Tour’s anti-doping program and Singh was sanctioned on February 19th, but after he appealed the Tour contacted Wada and said in a statement yesterday that: “At that time, Wada clarified that it no longer considers the use of deer antler spray to be prohibited unless a positive test results.”

Speaking at a press conference today ahead of the Wells Fargo Championship, McIlroy said: “Wada made a decision which said that deer antler spray was no longer on the prohibited list so there isn’t really much they can do about it.

“My stance on it is that Vijay didn’t know he was doing anything wrong, and if there is no intention there I don’t see any reason to unfairly punish him.”

McIlroy was with former world tennis number one Wozniacki in Monaco last month when they were woken at 6am by drugs testers, a situation golfers will have to get used to when the sport falls under Olympic jurisdiction from 2016.

“Most other professional athletes have to fill out a whereabouts form that is three months in advance,” McIlroy added. “If we are going to be part of the Olympics it’s something we’re going to have to do too and I completely don’t mind that at all.”

McIlroy is back at the scene of his first PGA Tour victory this week, but a repeat of his spectacular closing 62 in 2010 might well be out of the question.

Bad weather over the winter has taken its toll on several of the greens at Quail Hollow, with two of them — the eighth and 10th — dug up and relaid just a week before the start of the Wells Fargo Championship.

All 18 bentgrass greens will be replaced with Bermuda grass when the tournament is over, but McIlroy is taking a pragmatic and light-hearted approach to the situation.

“The greens are the best on tour usually, it’s just unfortunate that they are not quite up to the standard they usually are,” the world number two told a pre-tournament press conference.

“It’s no big deal, the rest of the golf course is in phenomenal shape and it’s going to be the same for everyone. The best player at the end of the week is still going to win.

“If you start missing putts I guess you have to accept it. I don’t mind because I’m not a guy that relies on my putting per se, so it will eliminate quite a lot of the field and I don’t mind that at all.”

As for the rest of his game, McIlroy believes it is in better shape than might be thought after a tie for 25th on his last appearance at the Masters last month.

“I feel good,” added the Northern Irishman, who won five times around the world last year but has struggled to rediscover such form in 2013.

“I had two sevens on the back nine on Saturday (at Augusta) but I played solid on Sunday, shot 69 and at least came away with some positives.

“I’ve done some good work with Michael (Bannon, his coach) in Florida last week, the game feels in good shape so hopefully I can continue that this week.”