Jason Taumalolo looks set to miss a month after suffering a calf tear on Sunday against the Newcastle Knights.
The Cowboys are hoping to get Taumalolo back before the end of the season but won't rush him back.
Taumalolo is joined on the sidelines by hooker Reece Robson, who will miss the rest of the season.
Robson suffered a significant hamstring tear and will be put on ice for the rest of 2020.