Western Sydney Wanderers midfielder Kearyn Baccus cut a frustrated figure after being substituted in the 57th minute in the club's FFA Cup quarter-final win over Melbourne City.
With City scoring in the 53rd minute to cut the Wanderers lead in half, Baccus was replaced by Marc Tokich minutes later and the 27-year-old wasn't impressed.
The midfielder marching straight down the tunnel, pulling his shirt off and throwing it away in anger.
While coach Markus Babbel didn't seem too concerned by the incident after the game, saying he'd speak to Baccus on Thursday, Mark Bosnich wasn't impressed.
"Are you serious?” Bosnich said on Fox Sports post-game.
“I don’t like it...I understand him being upset at the manager, but me personally I was brought up as a young apprentice at Manchester United that if you did that you’d be in big trouble.
"Maybe he’s got something going on in his own personal life. It doesn’t look good at all, not for him, not for the club, not for anyone.”
Baccus also found himself in hot water earlier this year when he refused to play against Perth Glory while trying to force through an overseas transfer.
The midfielder has been with the Wanderers since 2014 and has been joined in the senior squad by younger brother Keanu.