Fremantle wingman James Aish could miss multiple weeks because of concussion in the fallout from the bump that led to Richmond forward Rhyan Mansell's three-match suspension.
Aish, who has a history of head knocks, was on the receiving end of a high bump from Mansell during the Dockers' 15-point loss last Saturday night.
The 27-year-old has missed just one game for Fremantle across three seasons and will sit out the away clash with GWS on Saturday under concussion protocols.
Dockers coach Justin Longmuir has conceded Aish is no certainty to return against Essendon in round 15.
"He could miss one. This isn't Aishy's first concussion though, so we'll take extra precaution and make sure we get him right," Longmuir told reporters on Wednesday.
"I'm a senior coach and hoping for best-case scenario, but given Aishy's history and situations that he's had in the past, he could miss more than two.
"That's the unpredictability with concussion."
Fremantle ruckman Sean Darcy (hamstring) will also miss this week's trip to Sydney but is targeting a return against the Bombers at Optus Stadium.
Longmuir will again back Luke Jackson to play the lead ruck role against Giants duo Kieren Briggs and Lachie Keefe, with key forward Josh Treacy providing support.
"The ruck combo was competitive on the weekend," Longmuir said.
"Jacko competed really well, followed up really well, and I thought Josh Treacy gave us a really good contest in there.
"He lacks a little bit of height for a true ruckman but he lacks nothing in the way he competes and the way he follows up at ground level."
Re-signed Dockers veteran Michael Walters will likely feature in the starting line-up against GWS, after kicking two goals as the substitute against the Tigers on return from a calf injury.
Ball-winner Jaeger O'Meara is available after serving a one-match suspension for a dangerous tackle.
