Fremantle will remain without ruckman Sean Darcy due to a knee concern, with the Dockers tall pulling up sore after Wednesday's training session.
Darcy missed last week's win over GWS due to the injury, with the Dockers hoping the 26-year-old would get through training ahead of this weekend's bout with Port Adelaide.
The first-string big man was assessed in the lead-up to Round 11 but has since reported an issue with his knee, meaning ruck-forward Luke Jackson will resume his role as the starting ruck option for Longmuir.
Speaking with SEN WA, the Dockers coach revealed Darcy won't feature at any level this weekend and reaffirmed his value to the club amid calls for the Western Australian side to favour Jackson instead.
"We've got to get him back to full fitness, and that's not going to happen this week," Longmuir said on Thursday morning.
"He didn't pull up great after the session yesterday. Not bad, just now quite 100 per cent. So he won't be available for selection this week.
"Sean's ruck form is coming along nicely. The media can sometimes get tunnel vision with the way we analyse games. Three of four weeks ago, when we played Adelaide, Sean was one of our better players.
"I think Sean has got a lot to offer our footy club, clearly Jacko does as well."
Jackson has thrived in Darcy's absence this year, recording at least 16 disposals, 28 hitouts and an average of 3.6 clearances in his five games as the sole ruck option under Longmuir.
The Dockers won three of those five games, while Fremantle are winless in their two matches with both ruckmen featured.
Darcy is likely to return next week when Fremantle head to the Gold Coast to face the Suns, who are one of this year's leading premiership contenders.
Fremantle could return to the top eight this week with a win over the Power, which could place them within reach of the Suns should they fall to St Kilda this weekend.