World number three Justin Thomas has apologised for using a homophobic slur during the third round of the Sentry Tour of Champions in Hawaii.
Television microphones picked up the American's remark after he missed a five-foot par putt on the fourth hole.
In a statement, the PGA Tour said his comment was "unacceptable" and the former world number one is expected to be fined for his conduct.
"It's inexcusable. First off, I just apologise," said Thomas, 27.
"I'm an adult. I'm a grown man, there's absolutely no reason for me to say anything like that. It's terrible. I'm extremely embarrassed.
"It's not who I am, it's not the kind of person that I am or anything that I do.
"Unfortunately, I did it and I have to own up to it and I'm very apologetic."
Thomas is tied for fifth place after finishing his round with a five-under 68.
He is four shots behind co-leaders Harris English and Ryan Palmer, who are on 21 under par with one round to play.
- Your diet's carbon footprint: Calculate the impact and how to change it
- A Perfect Planet: Sir David Attenborough shows us the forces of nature that support the Earth