Star Fremantle midfielder Brad Hill could miss the start of the AFL season after injuring his quad at training on Wednesday.
Hill injured his right leg during a drill and didn't complete the session.
The 2017 club champion will undergo scans to determine the extent of the damage.
The potential loss of Hill for the round-one clash with Port Adelaide would be a huge loss for the Dockers.
Hill, a three-time premiership winner at Hawthorn, starred in his first season at Fremantle, averaging 23.5 possessions per game last season.
His brother Stephen Hill has battled a calf injury during the pre-season but is a chance to return in Sunday's practice match against West Coast at HBF Arena in Joondalup.
Troubled midfielder Harley Bennell returned to the club on Tuesday after his eight-week exile came to an end.
Bennell was banished to WAFL club Peel Thunder in January after being involved in an alcohol-fuelled altercation with a bouncer at a Fremantle night spot.
The former Gold Coast star is still nursing a calf injury but he's a chance to play for Peel Thunder before round one of the AFL season.
Teammate Joel Hamling says Bennell has the potential to win a Brownlow medal if he can overcome his injury and off-field issues.
