Canberra co-captain Josh Hodgson requires surgery on a fractured thumb and will miss up to eight weeks of NRL action.
Hodgson was injured in the Raiders loss to North Queensland in Canberra on Saturday and didn't feature in the second half.
The hooker missed 13 games with a knee injury last season and Canberra struggled without the England international.
Hodgson joins a growing injury list at the Raiders with fellow internationals Jordan Rapana, Joey Leilua and John Bateman sidelined.
Canberra could also lose three of their best players to State of Origin with Josh Papalii, Jack Wighton and Nick Cotric in the selection frame.
Meanwhile, Cowboys centre Justin O'Neill was reportedly rushed to hospital in Canberra after rupturing his spleen on Sunday.
North Queensland prop Matt Scott's chances of a Maroons recall in game one on June 5 appear over after he partially dislocated his shoulder against the Raiders.
Scott will get scans and could be out from anywhere between two weeks and six months.
Australian Associated Press