A war is brewing behind the scenes of the Australian Open over player pay and power.
The governing body behind the men's professional tour, the ATP, seems set to lurch into crisis after the Open, with suggestions of a player mutiny.
At the annual players meeting in Melbourne on Saturday, players council president Novak Djokovic reportedly voted against extending the tenure of ATP chief executive Chris Kermode, a move that could set off dramatic changes in the tour's direction.
Djokovic wouldn't confirm his vote, citing the meeting's confidentiality.
"The decision hasn't been made on the president," Djokovic said.
"Whether there's a renewal or not, it's going to be decided in the next period."
Also on Sunday, Roger Federer conceded "a lot is happening" behind the scenes and he would take soundings from other players on their views.
"It's definitely interesting times, I'd like to call it, not bad times in our sport. It's maybe also a bit of a transition time. So it will be interesting to see what's going to happen," he said.
The ATP board will vote on the organisation's leadership after the Open.
If Kermode is replaced, one man who has been touted as a replacement is Tennis Australia and Australian Open boss Craig Tiley.
Australian super-coach Darren Cahill railed against a change on Twitter, saying Kermode had brought "big increases in prize money, pension plan, new events, doubles initiative supporter, new progressive rules for injured players ... facility upgrades".
"I'd be stunned if Chris Kermode is removed. ATP needs stability right now," he wrote.
Player council member Vasek Pospisil is a further agent for change, arguing for increases in prize money at grand slams.
"Grand slams which report hundreds of millions of dollars in profit ... yet we get less in prize money than 10 per cent of their revenue," he wrote in an email sent to players ranked between 50-100.
"Our system is broken ... it's time for a change."
Stan Wawrinka and Nick Kyrgios have also expressed support for Kermode, showing the divided nature of the men's game.
