TV commentators on Paramount+ initially flagged a potential hamstring tear as the reason for the 33-year-old A-League captain being stretchered off in the 78th minute of the Western Sydney Wanderers' match against Melbourne City. 

It's now been confirmed that Williams has torn his hamstring off the bone by an APL insider.

Minutes before fate struck, Williams - clearly in some discomfort - was treated by a Wanderers physio but cleared to continue.

With Williams turning 34 in July, a prolonged absence could be potentially career threatening for a player who has already spent nearly two-and-half years of his career recovering from serious injuries.

The ex-Middlesbrough captain previously sustained an ACL rupture 12 years ago and the hex hit again with back-to-back Achilles tendon ruptures which forced him out of Australia’s squad for the 2014 World Cup, and ultimately led to Boro cutting him loose in 2016.

Williams had begun the season strongly, the most reliable figure in a leaky Wanderers defense in his five appearances this season.

His ill fortune could open the door again for vice-captain Ziggy Gordon, who played every minute of last season as either a fullback or stopper but has yet to feature so far this season.