Jason Taumalolo is facing four weeks on the sidelines after scans revealed the Cowboys ace tore a calf muscle against the Knights on Sunday.
The sight of Taumalolo hobbling up the tunnel of McDonald Jones Stadium in the 53rd minute would sent shivers up the spines of North Queensland fans.
The Cowboys announced on Monday that their star forward would miss up to a month.
The Tongan international only managed 41 metres in his 32 minutes on the field in Sunday's 12-0 loss to the Knights, which is far below his usual standards.
In the round seven 32-30 win over the Knights in Townsville, Taumalolo ran for 297 metres in his 70 minutes input.
"It's a calf injury but I'm not sure of the severity. It's a fresh injury – he had no niggle coming into the game," said Cowboys coach Josh Hannay.
Match Highlights: Knights v Cowboys
Calf muscles have a funny way of hanging around – like hamstrings – not allowing players to come back as early as they hoped.
Asked if Taumalolo might have played his last club game of 2020, Hannay said: "I wouldn't have a clue but I hope not.
"He's obviously key for us but as I said, I'm not sure how severe it is."
After scoring six tries in the 31-30 loss to the Rabbitohs a week ago, the Cowboys couldn't cross the line against the Knights. Hannay said the 40km/h wind blowing down the field didn't allow either side to use the ball out wide.
Still, the Cowboys kept the Knights to two tries in a decent defensive display.
It is the last-tackle options and kicking game that Hannay wants his men to work harder at getting right.
Taumalolo forced from field
"I didn't like our last plays. I thought our kicking game was poor, especially in the second half.
"I thought we worked hard in the first half to give ourselves a chance," he said of the 6-0 half-time score.
"We showed some effort and some resolve that we haven't seen a lot of for a while at this club. So we gave ourselves a chance but we lacked control in the second half with our last plays to build any pressure.
"Mitchell Pearce did a really good job for them – he's been doing it his whole career – in turning teams around and kicking the death out of football sides. I thought that was the difference.
"I also thought we could have easily rolled over and conceded a few more tries in that second half and earlier in the year we would have.
"But more and more over the last four or five weeks we've showed a resolve to defend our line and handle pressure."
Get Caught Up: Round 15
He wants that in spades for the remaining five rounds.
"We've got to continue to play, to demonstrate, a toughness about our football – that the jersey and the club mean something."
Even though star fullback Valentine Holmes is no guarantee of making his return from an ankle injury next weekend, Hannay indicated he may look to shuffle his spine to spark the team's attack.
First-choice hooker Reece Robson missed the Knights clash with a hamstring problem.
The Cowboys have another long trip to Sydney next week to play the Sharks at Netstrata Jubilee Stadium at Kogarah.