Pearce broke his right tibia in round nine last season, ruling him out of the remainder of the year.
The 21-year-old suffered a partial fracture in the same leg while completing a training drill last week. He will be in a cast for six weeks and a return date is unknown at this stage.
“Alex won’t need to undergo any surgery to the leg, however he will be required to wear a weight-bearing cast for six weeks to maximise his rehabilitation,” general manager football operations Chris Bond said.
“It’s just an unfortunate incident that happened during a standard running session with our rehab group.
“Alex is in good spirits despite the setback, and he and our medical team are focused on ensuring he has an impact in the 2017 season.”
Pearce has played 21 games in two seasons at the Dockers.