Patrick Reed's caddie has been barred from Sunday's Presidents Cup singles after he was involved in an altercation with a spectator on Saturday.
Reed has been heckled throughout at Royal Melbourne following his controversial penalty in the Bahamas last week where he was docked two strokes for improving his lie in a waste bunker.
Saturday's incident occurred after Reed and his playing partner Webb Simpson were thrashed 5&3 by Hideki Matsuyama and CT Pan in the morning fourballs.
Reed's caddie Kessler Karain, who is also his brother-in-law, confronted the fan, who shouted at the player from three feet away, as he and Reed were driving a golf cart following the match.
A video posted on Twitter showed Karain gesturing angrily near a temporary seating terrace at the course before turning to board the cart and drive off with Reed.
Karain later issued a statement which read: "After hearing several fans in Australia for three days, some had taken it too far. I had had enough.
"I got off the cart and shoved him, said a couple of things, probably a few expletives. Security came and I got back in the cart and left. Unless his bones break like Mr Glass, the most harm done was a little spilled beer, which I'm happy to reimburse him for."
The PGA Tour reacted to the incident by barring Karain from caddieing for Reed in Sunday's singles match against CT Pan.
"Following an incident that took place on Saturday at the Presidents Cup involving Kessler Karain and a spectator, Karain will not return to caddie for Sunday's final-round singles matches. We will have no further comment at this time," read a statement.
Reed accepted the decision, saying: "I respect the Tour's decision. We are all focused on winning the Presidents Cup tomorrow."
Karain is set to be replaced by Reed's swing coach Kevin Kirk.
Woods calls for respect
Team USA captain Tiger Woods has asked fans to be "respectful" towards his team in Sunday's singles.
"There's obviously some yelling. There's people who have had a lot to drink and have gone over the top," he said.
"Bipartisanship is part of playing in team matches, whether you're home or on the road; it's part of the deal.
"As long as the fans are respectful, and that's all we ask is for them to be respectful, and hopefully they will be excited tomorrow and into the matches and be very respectful of all the players."
Internationals captain Ernie Els, however, said the International team had suffered worse from the galleries at Liberty National, New Jersey, two years ago.
"We shut up and we get on with things. That's what we did in New York," the South African said. "This Aussie crowd, OK, they got a little bit boisterous this afternoon with a couple of beers, but which crowd doesn't? You take it and you move on."
Difficult week for Reed
Before Reed arrived in Melbourne, players on the Ernie Els-captained International team urged local crowds to give him a hard time, with Australian Cameron Smith accusing the American of "cheating the rules".
In a pre-tournament media conference, Reed denied cheating and said he had inadvertently breached the rule.
Some spectators have brought miniature shovels to the course and waved them at Reed. Others have worn shirts branding him "The Excavator".
Reed responded to the heckling on Friday by making a shovelling gesture with his putter after holing a birdie.
Despite Reed and Simpson losing in Thursday's fourballs and the foursomes on day two, the pairing were given another chance by captain Tiger Woods on Saturday morning but were well beaten by Matsuyama and Pan.
The American duo were dropped for the afternoon foursomes.
Reed, a captain's pick, has now failed to score a point in five successive matches when partnered up at team events, having been beaten twice with Woods at last year's Ryder Cup in France.