But he expects the sidelined Swans skipper to put his own devastation aside for the sake of helping his teammates.
Mills, 27, was on Wednesday ruled out of Saturday's decider against the Brisbane Lions after attempting to prove his fitness to return from a hamstring injury.
He strained the muscle on September 10 and would have needed to play just 18 days later, prompting coach John Longmire to scratch him.
The quick decision allows Sydney to focus firmly on the game, without the distraction of Mills' fitness as an ongoing narrative in the background.
But their captain, who played just seven games this year, will have to process his own personal heartbreak while supporting his teammates through to the finish line.
It is something Maxfield, who missed out on Sydney's drought-breaking 2005 flag after his season was ruined by injury, can relate to.
"I obviously feel for Callum, it's disappointing," he said on Thursday.
"But knowing Callum reasonably well, he's a strong character and he's a fantastic leader, a player who always puts the team first.
"He hasn't played a lot of footy this year but he's had a huge impact on the entire club and particularly the players.
"No doubt the next couple of days he'll be providing the support that they need."
Maxfield plans to reach out to Mills after the decider.
"I won't reach out to him prior to the game, I will after the game," he said.
"I'm sure he's got enough on his plate at the moment."
If Sydney win, Maxfield will present the premiership cup to the Swans' stand-in captain, likely Dane Rampe, and coach John Longmire.
He believed disruptions through the week wouldn't stop the Swans from triumphing.
The Swans took a charter flight to Melbourne on Thursday, with Mills joining his teammates.
"It depends which way you look at it," Maxfield said.
"I think sometimes you have some of your greatest wins when your planning isn't always that great.
"So you just take that on board, it is what it is, and you move forward."
Speaking after their arrival in Melbourne, assistant coach Dean Cox said Mills had done all that was asked of him at Wednesday training.
But a meeting involving the Swans medical and coaching staff then decided Mills' fate.
"There was always a risk with the timeframe," Cox said.
"So the training session was a certain amount of that and game loads are a lot different. The decision was made by everyone."
Cox praised Mills for his attitude throughout a tough season for the skipper.
"He's always put the team first. His approach, certainly through the year and also over the last few days, has been unbelievable through a really tough time," he said.
Cox added the Mills decision was not influenced by their decision to play Sam Reid in the grand final two years ago - a selection that backfired badly.
"You just have to play everything on its merits. Sam was a little bit different to Callum," Cox said.
The Swans have named an unchanged line-up, meaning utility Robbie Fox has held his place.
Dane Rampe has been named skipper in the absence of Mills.
