Dustin Johnson and Brooks Koepka are supposedly best buds. They hang out, they play golf, and even pump iron together. But reports have surfaced that the American duo came to blows after the Ryder Cup finished on Sunday.
Witnessess recounted how the US Ryder Cup duo were invited into the European Ryder Cup team room on Sunday evening. Johnson and Koepka joined the party but soon got into a heated exchange before having to be separated by other players and officials.
READ: DJ AND BROOKS IN HEATED EXCHANGE AT RYDER CUP
One witness has since claimed Koepka threatened to "flatten" Johnson.
It is also claimed that Johnson and Koepka had an alteraction on the flight over to the Ryder Cup in L'Equipe.
We take a look at the five possible reasons for Johnson and Koepka's bust-up...
#1 - HEAVY RYDER CUP DEFEAT
Let's face it, the Americans were favourites to win the Ryder Cup at Le Golf National last week - and they got absolutely battered 17.5-10.5.
Patrick Reed has already been sounding off on not playing alongside Jordan Spieth, as he did in the 2016 Ryder Cup, and he has even taken a pop at captain Jim Furyk. Perhaps it's just contagious in the US camp and Johnson and Brooks wanted to follow suit.
Johnson and Koepka played together in the Saturday foursomes, but went down to the solid pairing of Justin Rose and Henrik Stenson 2&1. Maybe one of them took a risk where it wasn't necessary, who knows?
Koepka - who took 1.5 points at the 2018 Ryder Cup - finished A/S with Paul Casey in the singles, while Johnson - who picked up 1 point - lost 2 down to Ian Poulter.
Their scuffle may have been a result of a shocking Ryder Cup for not just both players, but the entire US team.
#2 - DJ SAID HE COULD LIFT MORE
Dustin and Brooks spend a lot of their time together pumping iron in the gym.
Who knows, maybe DJ said he could deadlift 320 pounds but Koepka raised the stakes at 330.
This could have just been gym banter that got way out of hand.
#3 - 'I'LL RAISE YOUR ONE US OPEN WITH TWO'
Dustin might be World No.1 but he only has one major title coming at the 2016 US Open.
Brooks won two major titles this season when defending his US Open crown before going on to win the US PGA for his third career major.
Maybe the scrap happened because of major chat.
#4 - BROOKS' WILD TEE SHOT SAW A LADY LOSE HER EYESIGHT
Brooks was understandably left shaken by hitting a lady golf fan in the eye on the sixth hole during his Friday foursomes match.
While he went on to win that opening match alongside Tony Finau, to his credit, the incident no doubt left him a little pale.
Brooks has no doubt been worried about this lady ever since Friday morning - and sadly the latest news is not good as the lady has since lost sight in her eye and threatens to sue.
#5 - PAULINA GRETZKY
It was widely reported Dustin and Paulina's relationship went through a rocky period last month.