Taumalolo will seek further medical advice before deciding the appropriate course of treatment but the club expects the Tongan wrecking ball to spend up to a month on the sidelines.
Former Warrior Lachlan Burr and back-rower Shane Wright have been included in the reserves for the Saturday's clash with the Dragons and will come into calculations to replace Taumalolo.
It's capped a delicate week for Taumalolo, who was publicly questioned by Cowboys coach Todd Payten following a sub-par performance against the Panthers in round one.
Taumalolo recorded some of the lowest figures of his career at Panthers Stadium.
Payten was forced to defend his own decision to limit the powerhouse’s game time in the match with his 51-minute stint well below the 63-minute average Taumalolo has produced in the past four seasons.
The pair have since cleared the air with Payten declaring his post-match comments with the media had been well-received by the players overall.
"He [Taumalolo] knows he can be honest with me too," Payten said. "It's a two-way street and things are fine."
Payten's next line of discussions could be with star Valentine Holmes, who lost the fullback jersey to Scott Drinkwater in the pre-season.
The former Sharks premiership-winner linked well with Hamiso Tabuai-Fidow on the left edge but was vocal this week when asked about starting the year on the wing.
"Obviously I've played a bit before there in the past but ideally my position I like to play and the reason I came here, was to play fullback," Holmes said.
"That's why the club got me here but with a new coaching staff and new schemes to how we want to play it's a bit different now.
"I played on the wing at the Sharks and in rep footy, so coaches know I can play wing, but like I said it's not the position I feel like I can play my best footy at.
"It's a bit limited out there [on the wing], you can't really do too much but take yardage carries out of your end but I'm happy to do that.
"Just to be playing week-in-week-out is what I want to do."