Sydney Swans co-captain Callum Mills is expected to be sidelined for four to six weeks after scans confirmed a moderate grade calf strain.

Mills sustained the calf injury in the opening minutes of the match against Fremantle and was immediately subbed out of the game. 

Meanwhile, young forward Logan McDonald suffered an ankle injury in a marking contest in the second quarter and was unable to return after half-time.

McDonald will undergo further assessment in the coming days but is expected to miss approximately eight weeks with a significant medial ankle sprain. 

Executive GM, Football, Charlie Gardiner, said it is disappointing to lose both players for an extended period. 

"Callum is obviously one of our on-field generals and Logan has been building into some good form so we are disappointed to lose them for what looks like an extended period.

"We know they will both throw themselves into their rehabilitation and do everything they can to get back as quickly as possible."

This injury update is presented by Castlereagh Imaging. 

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