SYDNEY, AUSTRALIA - MAY 10: Callum Mills of the Swans looks upfield during the round eight AFL match between the Sydney Swans and the Essendon Bombers at the Sydney Cricket Ground on May 10, 2019 in Sydney, Australia. (Photo by Ryan Pierse/Getty Images)

The Sydney Swans' battle to make it past the first week of the AFL finals may be about to get a whole lot tougher.

Star defender Callum Mills is in doubt for the clash against the Greater Western Sydney Giants thanks to an ongoing Achilles problem.

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Mills has struggled with the Achilles injury since coming out of hotel quarantine. He was originally withdrawn from the Round 18 match against GWS after being exposed to COVID when attending the Wallabies' game at AAMI Park.

He returned in Round 20, but was pulled out of the Round 22 clash against the North Melbourne Kangaroos with the Achilles problem.

Mills was clearly far from his best, health-wise yesterday, and Swans' coach John Longmire confirmed in the post game press conference that it was the same injury causing the 24-year-old defender grief.

“It was a bit stiff in the warm-up but normally he warms up really well and away he goes…. He’s been able to get going even though he might look a little bit proppy in the warm-up,” Longmire said.

“It didn’t get any better today, particularly in that third quarter we were concerned he was putting himself at risk. We were worried about injury from that point. We really wanted him to keep playing. It would have been good for him. He hasn’t played a lot of footy over the past 6-7 weeks. It was putting him too much at risk.

“We don’t know. Clearly he will play if he’s OK, but obviously he has to be in doubt. We will have to see how he pulls up. He’s a little bit sore at the moment… It’s a bit too early.”