While his season hasn't lived up to the Queensland State of Origin fullback's lofty standards, Walsh's performance on Saturday showed he remains a key part of his side's finals ambitions.

The Broncos, on 22 points, are still a shot of making the top eight but will likely need to win their remaining three games after this week's bye — against Parramatta, the Dolphins and ladder leaders Melbourne.

But their already-slim finals chances were hit by the news of Walsh's injury, along with confirmation that five-eighth Ezra Mam will miss the remainder of the season.

Mam underwent surgery on a syndesmosis injury last week and will spend the next few weeks in rehab in the hopes the diminutive playmaker will be ready for preseason training later in the year, Ballard said.

Star prop Payne Haas (Lisfranc) and hooker Tyson Smoothy (ankle) have both avoided surgery.

"Payne will undergo some further testing in coming days before we can assess when he will return, while Tyson has begun his rehab work in the gym," Ballard said.

AAP