Golf crowds are usually among the tamest in sports, but PGA golfer Keegan Bradley said he was subject to a heckler Saturday who called him a “cheater” for anchoring his putter against his stomach.

Using a so-called “belly putter” is legal in golf for now, but the sport’s governing body, the United States Golf Association, is banning the practice starting in 2016.

As Keegan played the last hole of his round Saturday at the Tiger Woods World Challenge in California, he said he heard one spectator call him a “cheater.”

"It's very disrespectful, but it's fine with me," Keegan told, adding that it’s the first time he’s been heckled over his putting technique. "I've got to try to look at it as motivation to help me try to win this tournament."

In a statement, the USGA backed Keegan’s use of the belly putter.

"This is a deplorable incident, and there is no place in our game for this kind of behavior. As we noted when announcing proposed Rule 14-1b, it has been and remains entirely within the Rules of Golf for players to anchor the club while making a stroke. There should not be a shred of criticism of such players or any qualification or doubt about their achievements, and we think that it is inappropriate even to suggest anything to the contrary. Rule changes address the future and not the past. Up until now and until such time as a Rule change were to be implemented, golfers using an anchored stroke will have been playing by the Rules of Golf,” the sport’s governing body said. "We are sorry that Keegan had to experience this unfounded criticism from an obviously uneducated spectator. Instead, Keegan and other PGA Tour professionals should be commended for their maturity and grace in managing through a proposed change to the Rules of Golf."

Bradley, the 2011 PGA Tour Championship winner and St. John’s University graduate, didn’t let the heckler get the best of him. He finished second to England’s Graeme McDowell in the final round of the Tiger Woods tournament. McDowell bested Bradley with a score of 17-under par to Bradley’s 14-under par.

McDowell took home $1 million for finishing first, while Bradley earned $500,000.

“Great playing by @Graeme_McDowell today,” Bradley wrote Sunday on his Twitter account. “Dude was a warrior. Awesome week here at Sherwood. Thanks to the tiger woods foundation for a g8 wk.”