The 25-year old had to leave the track early during the session, and a Dockers official confirmed it had been an ongoing issue.
“Although we are awaiting the outcome of a scan, it appears that Shane sustained a tear to the plantar fascia in his left foot during a training drill today,” the official told AFL.com.au.
“While Shane will experience some pain and discomfort in the short-term, in the long-term he will benefit by having the plantar fascia released.
“He is expected to resume training in about two weeks.”
Kersten has played 29 games in his two seasons at Fremantle since crossing over from Geelong at the end of 2016 and comes out of contract at the end of this season.