Second-year Hawk Bailey Macdonald is expected to spend a period on the sidelines after suffering bone stress in his femur.
The 19-year-old reported discomfort in his upper leg following a training session late last month, before scans revealed bone stress in his femur.
Hawthorn High Performance Manager Peter Burge said Macdonald would now take part in a modified program.
“It’s unfortunate news for Bailey, who has had a strong pre-season to date,” Burge said.
"Bailey has already begun working through his rehab program and we will look to progressively increase his load in the coming weeks.
“With Bailey being a young player, we will take a conservative approach during his recovery.
"Thankfully, this injury has been detected early and Bailey is in a good position to allow it to heal as soon as possible.”
The youngster managed two games in his maiden season last year after making his debut in Round 12 against Port Adelaide.