Taking time out from the Swans' Brownlow Medal function in Sydney, Longmire said preparations would continue as normal for his team.
"He's obviously come out early in the week and we get on with our preparations," he said.
"We don't spend too much time thinking about it."
Longmire would not be drawn on the make-up of his own team, saying: ""It'll come down to what we think is right on the day."
The Hawthorn defender met with coach Alastair Clarkson on Monday and told him he could not guarantee his fitness after battling to overcome a hamstring injury in his left leg.
On Monday afternoon, Guerra informed his teammates of what he described as a "gut-wrenching decision", telling them his rehabilitation had progressed well but that he would simply run out of time to make a full recovery for the grand final.
Guerra sustained the injury in the last quarter of the Hawks' round 23 win over West Coast at the MCG.
"As desperate as I am to play on Saturday, I realised that I couldn’t guarantee to 'Clarko' or the team that I could do everything that would be asked of me in a Grand Final," Guerra told hawthornfc.com.au.
"It was a gut-wrenching decision to make and it was difficult to address my teammates and coaches today, but they know they have a job to do on Saturday and that needs to be their only focus right now."
Teammate and close friend Lance Franklin told 3AW on Monday night that Guerra's unavailability was "devastating news" for the club, and "pretty sad".
Guerra, 30, was a member of the Hawks' 2008 premiership side. He has tallied 236 games for Port Adelaide, St Kilda and Hawthorn, including 19 this season.
In better news for the Hawks, Luke Hodge was declared a certain starter for the game.
The Swans also received good news with star ruckman Shane Mumford cleared of any wrongdoing from an incident during Friday night's preliminary final against Collingwood.
An investigation of an incident involving Mumford and Magpie Chris Dawes was assessed but the MRP determined there was no reportable offence and the charge was dismissed.
Guerra's decision to withdraw leaves only Swan Ben McGlynn racing to be fit for the Grand Final.
McGlynn is trying to overcome a hamstring injury suffered in week one of the finals.
McGlynn has until Thursday to prove his fitness.
