The Wanderers said in a statement on Tuesday that the Swedish striker had sustained ligament damage to his foot during their 1-0 loss to Central Coast on Sunday.
Antonsson failed to finish the match due to the injury which followed a tackle by Mariners defender Jacob Farrell in the first half.
The Central Coast fullback was only shown a yellow card and AAP has contacted Football Australia (FA) to determine whether that was a sufficient sanction.
Referee Daniel Elder did not review the challenge on VAR.
Antonsson's injury is unlikely to allay tensions between the governing body and the Wanderers, who have had four players shown straight red cards over their last four games.
Unhappy Wanderers supporters unfurl a banner during their ALM match on the Central Coast. (Dan Himbrechts/AAP PHOTOS)
Chairman Paul Lederer is also being investigated by FA after he was seen berating match officials following a draw with the Newcastle Jets.
Western Sydney coach Marko Rudan served the first of his two-game suspension against the Mariners after slamming the inconsistency in refereeing and claiming there was a "stigma" attached to his club following a recent loss to Macarthur FC.
The Wanderers are winless in their last three games and clinging onto a top-six spot after appearing to be one of the early favourites to challenge for the premiership.
Rudan will be back in the dugout for the March 2 Sydney derby, but without Antonsson his task will have be made all the more harder.
12°C