Hegerberg bizarrely pulled out of Norway's second game against Switzerland mere minutes before the opening whistle, later citing groin tightness.
Roma striker Sophie Roman Haug has excelled in Hegerberg's absence, including scoring a hat-trick in the 6-0 thrashing of the Philippines.
But coach Hege Riise flagged Lyon star Hegerberg should be fit to feature in Wellington on Saturday in some capacity, provided she got through Friday's training.
"Ever since Ada's injury, she's been following the medical plan and been successful in every step of that plan," she told reporters.
"So we will see her in training today and see how how she reacts to that, like the last step before the game tomorrow. And we prepare for Ada to play or come in.
"So it will be a different scenario, we know we have two good No.9 targets forward and that's a luxury for me as a coach.
"So we will see who will be available and playing from the start tomorrow."
Riise, who won the World Cup as a player for Norway in 1995, previously scored against Japan in the 1999 tournament.
Japan put Spain to the sword with a brilliant counter-attacking 4-0 win in their final group game.
"Japan is an incredible team. Their pace is amazing and the passing they do as well is really impressive," midfielder Vilde Boa Risa said.
"So it's absolutely a great team.
"It's going to be a big challenge for us but we have done our very best to prepare for this game and hopefully it's going to be a good game for us.
"Japan has been good since the first game they played in the World Cup and it just shows the level they're at."
Spain will hope to quickly bounce back when they take on Switzerland in Saturday's other match at Eden Park.
The Swiss, for their part, are keen to find some goal-scoring rhythm and cause an upset.
"We're looking forward to it. We've played really well in our group stage," coach Inka Grings told reporters via a FIFA interpreter.
"We understand that Spain is one of the favourites.
"They carry that load and for us that means that anything is possible."
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