Nick Kyrgios has been ruled out of his ATP Cup match against Canadian Felix Auger-Aliassime with a back injury.
The world number 30 will be replaced by teammate and world number 48 John Millman for Sunday's tie.
The Courier Mail's Marco Monteverde confirmed the news early on Sunday morning.
Nick Kyrgios out of ATP Cup match against Felix Auger-Aliassime with a back injury. Will be replaced by John Millman.
— Marco Monteverde (@marcothejourno) January 4, 2020
It's not the first time the issue has riddled Kyrgios, with the 24-year-old suffering persistent back problems in 2015.
Kyrgios got off to a flying start in his first ATP Cup matchup, hammering German Jan Lennard-Struff to help his side claim overall victory, after Alex de Minaur also upset world no. 7 Alex Zverev.
Prior to the match the outspoken Tennis star pledged to donate $200 for every ace he hit during the team-based tournament to provide relief for the devastating bushfires which have ripped through large portions of the nation.
Kyrgios went on to his 20 aces against Lennard-Struff, raising a staggering $4000 in just his first match of the tournament.
He's just one of a number of Australian sporting stars to join the initiative and pledge to donate to the bushfire appeal, alongside NBL star Lamelo Ball, cricketers Chris Lynn and Glenn Maxwell.
