SYDNEY coach John Longmire will sweat on the fitness of game-breaker Callum Mills until hours before their elimination final against Greater Western Sydney.

Mills was substituted out of Saturday's 87-point hammering of Gold Coast, troubled by a nagging Achilles injury which has bothered him all year.

But Longmire said Mills had reported well on Monday and, with midfield stalwart Josh Kennedy (hamstring), will face fitness tests late in the week.

"Both we're not sure of just yet ... Callum has pulled up OK today, he's pulled up alright, so that's a good sign," Longmire said on Monday.

Mills, 24, also missed the Swans' previous two matches with the injury and has now completed only one match since round 17 as he struggles to manage the Achilles issue.

"If he was selected this week, we'd be expecting him to play the entire game. We actually need him to play right until the last minute.

"'The plan is to get the balance right between the right amount of rest and rehab, and the right amount of load. We'll see how he goes [in main training] on Thursday to see whether we declare him right or not."

Kennedy injured a hamstring in the final minute of the Swans' round 22 match against North Melbourne then missed the 87-point victory over the Suns.

Scans last week showed the co-captain has a low-grade strain and he was able to take part in light running over the weekend but is in doubt for the Swans’ first final since 2018.

"We'll have to wait until Tuesday before we get a first report on how Joey is progressing. We are naturally going to be a bit conservative with him."

Young gun Chad Warner stood out in a scratch match on Saturday and looms as the onballer most likely to step in if needed.

Warner played the first 12 matches of the season as he averaged 17 disposals a game and received a NAB AFL Rising Star nomination in round three.

The 20-year-old was sidelined with stress reactions in the lower leg but has returned to play four matches at the lower-level and press his claims.

"He missed about nine weeks with his injury, that's the only thing that has meant that he's been out of the team,” Longmire said. 

"He was very important early on in the year and if we need him to play this week, we're confident that he can play a really good role for us. 

"He and Dylan Stephens are two that we can draw upon if needed, James Bell has played as well through forward and midfield.”

The Swans tuned-up on the weekend with 21 goals from 55 forward-50 entries, as Lance Franklin starred with six goals and fellow tall forward Hayden McLean kicked two majors.

The 22-year-old McLean has been favoured over Sam Reid in the past two matches but the veteran was prominent in the scratch match on the weekend and will be considered for the finals clash with Greater Western Sydney.

Young forward-ruck Joel Amartey played limited minutes in that match due to ongoing groin soreness while prized draftee Logan McDonald sat out for a second week due to a slight crack in his cheekbone.