The top try-scorer in the NRL Telstra Premiership last year, Fusitu'a's absence would be significant blow to a Warriors side staring down the barrel of three straight losses for the first time since 2017.
Coach Stephen Kearney said the early indications were that Fusitu'a had suffered rib cartilage damage.
"Given it's a five-day turnaround to our next match I would anticipate he will be unavailable. It didn't look good," Kearney said.
"Looked like possibly rib cartilage, but I'm not 100 per cent sure."
The injury formed part of a disappointing night at the office for the Warriors, who twice blew leads against the Cowboys to suffer their fourth loss in six games this season.
The Warriors made five line breaks to North Queensland's one and broke 17 more tackles than the Cowboys. But without chief play-maker Blake Green – who was out for the second week in a row with a groin injury – they struggled to execute in the final third.
Kearney drew comparisons to his side's late collapse against South Sydney in round five – in which they gave up a 12-point lead to lose 28-24 – as the Warriors once again failed to go on with the job.
"In a way it feels a bit like last week to be honest. Just one that we let slip," Kearney said.
"I thought we did some really good things out there but lacked composure at times, and just really didn't do a good enough job in trying to build some pressure.
"We had a number of opportunities to build some pressure and just didn't execute well… it frustrated the group.
"We could have done better in the last 20 minutes, but I thought we could have done a lot better right through the game."
Things don't get any easier in round seven when they travel to AAMI Park, a venue where they haven't won in their last four games dating back to 2015.
But Kearney said he was confident there would be no repeat of last year's 50-10 Anzac Day drubbing.
"The circumstances were a little bit different last year. We came off a really good win against the Dragons [in Auckland] into a really tough match which we anticipated against Melbourne, and we weren't ready for that," Kearney said.
"But we will be ready for this one."