Broncos captain Adam Reynolds will be sidelined for three months after rupturing his bicep in Friday night's loss to Sydney Roosters.
Reynolds underwent scans on Saturday which confirmed the extent of the injury, but he is expected to return later in the season.
"He will have surgery early this week and be out for 12-14 weeks," Broncos head of performance Dave Ballard said.
Outside back Jesse Arthars also required surgery after x-rays confirmed he had broken his jaw against the Roosters.
“Jesse sustained a fractured jaw and underwent surgery today. He will miss 6 weeks," Ballard said.
Broncos coach Kevin Walters will turn to former Wests Tigers five-eighth Jock Madden to replace Reynolds, with Ezra Mam to move to halfback.
However, Madden is sidelined with a pectoral muscle injury and may not be fit for Friday night's match against Parramatta.
"He is a chance next week," Walters said of Madden. "It was a one to two-week injury, but I haven’t had a chance to talk to the doctors about Jock and his return.
"He would be an outside chance against Parramatta. We will just have to wait and see.
"We would prefer for guys to not get injured, but it gives us an opportunity to have a really good look at Jock for the next 12 or 14 weeks."
Billy Walters moved from hooker to the halves after Reynolds left the field early in the second half and may be another five-eighth option if Madden is unavailable against the Eels.
Reynolds has only played five matches in the opening nine rounds, while Mam, Payne Haas and Selwyn Cobbo have also missed games through injury, but Walters said he was happy with Brisbane's depth.
"We have got good depth. I’m more concerned about how we played [on Friday night]. We need to fix that," Walters said.
"We will get Adam back I am pretty sure before the year is out and also Jesse."
