Cale Hooker will be on a limited program for the next three weeks after injuring his hamstring.
Essendon confirmed on Saturday that Hooker had suffered a minor hamstring strain during pre-season training.
The injury was picked up after Hooker noticed symptoms post-training, with Essendon making the decision to place him on a modified program.
Essendon's general manager of football Dan Richardson said it was only a minor setback for the 30-year-old.
“While not acute, Cale presented with symptoms post-training and after consultation with our medical team a decision was made to place him on a modified program for the next two to three weeks,” he said.
“It is only a minor strain, and given he has had a solid pre-season to date we are confident it will not have a major impact on his preparation."
Hooker impressed at both ends of the field in 2018, starting the year up forward before switching to defence early in the season.