GUN SYDNEY midfielder Callum Mills is in serious doubt for the first week of finals after being subbed out of the match against Gold Coast due to Achilles soreness.

Mills appeared to be restricted during the pre-game warm-up and then throughout much of the match, until the Swans finally pulled him from the game just before three-quarter time.

The 24-year-old has been managing Achilles tendinitis for much of the season and missed the Swans' past two matches due to the injury, but was recalled to the team to build fitness and touch ahead of an Elimination Final next week.

"While he was a little bit stiff in the warm-up, normally he warms up really well and away he goes. That's certainly been the case this year," coach John Longmire said after the match.

"It didn't get any better today and after half-time in particular we were concerned that he was putting himself at risk. We were worried about injury at that point.

"We really wanted him to keep playing. It would've been good for him, he hasn't played a lot of footy over the last six or seven weeks, but it was putting too much at risk so we had to call the sub.

"He'll play [next week] if he's OK, but he's obviously got to be in doubt."

The Swans are still not sure whether they will be able to call on Josh Kennedy for the start of their first finals campaign since 2018, after the co-captain strained a hamstring last week.

But second-year onballer Chad Warner could be in line to replace Mills if needed, after impressing in his fourth scratch match since returning from stress-related soreness in his lower leg.

SWANS v SUNS Full match coverage and stats

Lance Franklin was quickly back to his best after being rested last week, kicking six goals and moving as well as he has all year in an imposing display.

Jake Lloyd was also managed last week and returned to collect a team-high 36 disposals.

"[Franklin] said he felt really good today. I thought he and Jake were both running on top of the ground, they needed that week off and both of them came back and performed strongly," Longmire said.

"While [Franklin] was playing regularly, he wasn't able to really go and put the hammer down, but he was able to do that last week and get himself in good nick for this week.

"Everyone needs to do that now and then, to feel good about themselves and also for the sake of injury prevention."

Gold Coast coach Stuart Dew said after the match that the club has assured him that he will be their coach next year.

The Suns progressed from five wins and a draw in 17 matches last year to seven wins this season, but Dew said he is also confident he has the support of the playing group that is committed to staying together.

The fourth-year coach added that the club would look to boost their tall stocks and midfield depth in the coming months but doesn't expect there to be any significant departures.

"Our players are really confident that this is the group. They spoke about that before the game, that this is the group to see it through and stick together," Dew said.

"That's the main message for all of us inside the footy club.

"We see ourselves as the first group to commit, the first group to work together and the first group to see this through."