But former Steel player and now assistant coach Liana Leota is ready to suit up if needed and has been named as a replacement player for the ANZ Premiership game.
Coach Wendy Frew confirmed Heffernan, 25, was doubtful as they waited for her injury to be properly assessed.
Leota, 40, played for the Steel from 2008 to 2011, had a three year stint with the Central Pulse and played in the Super League in the United Kingdom, where she also coached.
Former Northern Stars player Khanye’-Lii Munro-Nonoa has also joined the team as a replacement player.
"Obviously no team wants to be in a position where you’re having to look at alternative options, but the reality is we have a couple of injuries which need to be managed so the smart decision here is to ensure we have good backup on the bench if we need it,'' Frew said.
“While I’m not sure Liana expected to be packing her sneakers and playing kit, we are lucky to have someone of her netball pedigree available and willing to step up if we need her to.''
Heffernan is the second casualty for the Steel.
Defender Dakota Thomas had already been ruled out after carrying a niggle. Southern Blast defender Holly McRae will replace her.
