The 33-year-old joined Celtic in 2007 from Hibernian and has made over 490 appearances for the Bhoys in all competitions.
The Scotland international is yet to agree a new deal at Celtic and he is reportedly weighing up his options. Brown is out of contract at the end of the season, and he has been locked in talks with Celtic chief executive Peter Lawwell over a new deal.
He continues to be one of the key players for Brendan Rodgers, but Callum McGregor is now keeping him out of the team.
Brown, who is on £25k-per-week wages at Celtic, is now facing a massive decision over his future. Western Melbourne have won a spot in the A-League for the 2019-20 season, and want Brown to be their marquee signing.
They are weighing up a lucrative offer, and it remains to be seen what Brown decides on his future. Celtic have shown they can cope without him, but losing him would still be a big blow for the Bhoys.