Daniel Arzani is expected to escape sanction from club side Melbourne Victory after a photo was circulated which showed the Australia international playing for an amateur team in Sydney.
Arzani turned out for Coogee United, his junior club, in a sixth division game last Saturday.
Victory declined to comment but informed AAP that Arzani's behaviour would be addressed when players begin to return to preseason training later this week.
The Eastern Suburbs Football Association (ESFA) also declined to comment but said they were conducting an investigation into claims Arzani had played for Coogee United as a ring-in. ESFA's rules dictate that players must be amateur and must be officially registered with the league.
Arzani is not expected to be fined for his actions, although new Victory boss Patrick Kisnorbo is likely to have taken a dim view of his behaviour. It is also a bad look for Arzani, 25, to be playing for an amateur team on a rain-soaked pitch and risking injury.
The seven-cap Socceroo has endured a torrid run with injury over the early part of his career. He has only recently worked his way back into the national team setup under Graham Arnold, called up for June's World Cup qualifiers against Bangladesh and Palestine.
It was the first time Arzani had won a cap in close to six years and came after a sterling season for Victory in the A-League Men. Upon his recall to the Socceroos, Arzani credited since-departed Victory boss Tony Popovic for helping him rediscover the form which once made him one of the most-coveted Australian youngsters.
"The biggest takeaway for me working under the boss [Popovic] this season has been the mental side of the game," Arzani said in May. "It really helped with the team and the environment that I was in this year.
"We were very competitive, very professional, and it was a really great bunch of lads.
"They all got around me, they helped me out a lot, and I'm in a really good place right now."
Arzani made headlines as a teenage prodigy, earning a move to Premier League giants Manchester City as a 19-year-old, just months after becoming the youngest player to appear at the 2018 World Cup in Russia.
Arzani's time in Europe, however, was cruelled by injury. Man City arranged a two-year loan deal at Celtic for Arzani upon his arrival in the United Kingdom, only for the teenager to tear his ACL just 20 minutes into his Hoops debut. Nearly two years would pass until Arzani made another senior appearance -- on loan at FC Utrecht in the Netherlands -- but, after loan stints in Denmark and Belgium as well, Man City did not renew his contract and he returned to the A-League in July 2022.