Dunkley didn't train at Springfield on Tuesday and had his right calf strapped in a compression garment.
The midfielder exited last Thursday's win over Richmond after three quarters, saying post-game he thought he had corked his calf.
Small forwards Callum Ah Chee (concussion) and Lincoln McCarthy (suspended) will also miss Saturday's date with the 1-14 Eagles.
Veterans Dayne Zorko, Daniel Rich and Jack Gunston all trained on Tuesday but are no guarantees of playing, the latter two in a training block and Zorko being managed after a string of soft-tissue injuries this year.
Brisbane play Melbourne at the MCG and Geelong at the Gabba in the two weeks that follow the visit of the Eagles. They are likely to need five wins from their remaining eight games to secure a top-four berth.
At 11-4, the Lions are third and two wins behind the top two of Collingwood and Port Adelaide (both 13-2).
"We're previewing West Coast, we're not looking at Melbourne at all," Lions vice-captain Hugh McCluggage said.
"But we understand that West Coast, Melbourne Geelong (are) three games that can really either set our season up or put us back with a pack.
"So we understand that that's a really important block of footy for us.
"We see the teams that win the premiership most years, they all start in different ways.
"But the common thing is that they build the last few rounds and then into the finals. So that's a really important thing to do."
Brisbane have the cattle pushing for a chance, with Deven Robertson enjoying midfield time after Dunkley was substituted and Kai Lohmann a chance of returning to replace McCarthy.
West Coast's percentage improved to 49 after a tight loss to St Kilda last week that followed a 171-point belting from the Swans.
"Nothing changes for us," McCluggage said of the Eagles' plight.
"A lot of our players have been in that position before ... in 2017 we saw it as an opportunity to knock them off, an opportunity to test yourself against the best.
"It's exactly the position we were in."
Western Bulldogs recruit Dunkley has proved a prime midfield addition thanks to his defensive presence alongside ball-magnet Lachie Neale.
He has averaged 25.53 disposals, 6.73 tackles, 5.33 clearances and 13.47 contested possessions so far this season.
"We're hoping that he can get up but if he doesn't, Dev Robertson played in the midfield when (Dunkley) went down in the last quarter and did some really nice things," McCluggage said.
"We've got lots of options playing in the VFL and lots of depth. You're going to lose players, but hopefully we can cover that."
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