WESTERN Bulldogs young gun Sam Darcy is set for another stint on the sidelines due to an unusual lung problem that has emerged in recent days.

The 2021 No.2 pick didn't play for Footscray on the weekend due to illness and had reported breathing difficulties over the past week, which required further investigation. 

Subsequent scans have discovered a small hole in his lung that has leaked some air between the lung and chest wall. 

Darcy is expected to make a full recovery and will heal naturally, rather than requiring surgery. 

It continues a frustrating start to life in the AFL for the son of Western Bulldogs great Luke. 

Darcy arrived at the Whitten Oval dealing with a stress fracture in his foot and missed the first half of his debut season, before strong VFL form prompted Luke Beveridge to pick him late last year.

Darcy featured in the final four games of the season, including the elimination final loss to Fremantle, and looked impressive over the pre-season.

After starting the 2023 campaign as one of the favourites for the AFL Rising Star, Darcy was left out of the side after round two and has managed only two senior appearances, following the arrivals of Rory Lobb and Liam Jones.

The Western Bulldogs will be without Adam Treloar for Saturday night's clash against Carlton and could also be missing Jamarra Ugle-Hagan for the game.

The 2020 No.1 pick will need to prove his fitness later in the week after suffering an adductor injury in the win over Greater Western Sydney on Saturday night.