Sydney FC are searching for two of their own "fans" who attacked midfielder Robbie Middleby in the Sydney Football Stadium car park after Sunday's A-League win over Wellington.
Middleby was assaulted by two fans wearing Sydney FC scarves around their heads and faces after the 1-0 win, in an attack reportedly motivated by his move to North Queensland Fury next season.
The 33-year-old said only the arrival of his wife Melissa at the scene prevented him from being badly hurt.
The two men are now facing a life ban from A-League matches and possible legal action if caught.
"I was just walking along, and then I hear a guy saying 'You're f***ing leaving us are you Middleby? He must have jumped out from behind a car," Middleby told the Sydney Morning Herald's website.
"His mate just stood there, and he kneed me and starting throwing punches."
Middleby, who did not play in the match, said his wife ran over to defend him and he feared the attacker would turn on her.
"I thought he was going to attack her, so I threw a punch or two, and then my mate, who was also at the car, came over as well," Middleby said.
"That's when the two of them ran off."
Middleby said he did not want the culprits to get away with the attack.
"Other people shouldn't be thinking in future they can do this sort of thing, and nothing will happen," he said.
"Never in my career have I experienced anything like this. It's a disgrace."
Sydney FC released a statement on Thursday evening saying they were taking "all possible steps" to identify the men.
It is believed Middleby has given a detailed description of the men and the club is reviewing security footage to try and identify the culprits as well as asking the club's supporters group for assistance.
"The cowardly confrontation is completely unacceptable and the club will continue working closely with SFS management and Football Federation Australia to ensure that those responsible are held accountable," the club's statement read.
"The club will ensure that every avenue of investigation is pursued to identify the culprits, and the strongest possible penalty will be applied once they are found, with the pair facing life bans from all Sydney FC matches and possible legal action.
"Sydney FC enjoys a great relationship with its supporters, and will continue to do so into the future despite the behaviour of two individuals who have forfeited the right to call themselves Sydney FC fans.
"Sydney thanks its fans for their ongoing support and is urging anyone with any information about the incident to contact the club and assist with the investigation."
Sydney coach John Kosmina did not want to comment on the incident with both Middleby and chief executive Stefan Kamasz set to address the media on Friday morning.