Michael Hurley has injured his right shoulder in what is a major blow to an already depleted Essendon line up.
The key defender had just returned from a month on the sidelines with an AC injury to his left shoulder injury.
Dr. Rowan White described the issue as potentially a "really nasty injury".
"If internal damage it could be weeks (on the sidelines)," White said on Triple M Footy.
Trainers assisted Hurley to the rooms prior to half time.
A number of key players are already on the sidelines for the Bombers, including skipper Dyson Heppell, Devon Smith and Joe Daniher.