Superstar North Queensland lock Jason Taumalolo has been ruled out for the next six to 10 weeks, in a major blow to the club.

Taumalolo - whose inspirational round one performance guided the Cowboys to a win over the Dragons - was injured in Friday night's loss to Brisbane.

Scans on Monday revealed a grade three medial ligament injury for the Tonga star, who is now set to spend a couple of months on the sidelines.