Sydney Swans ruckman Sam Naismith's long wait to return to the field will be delayed after undergoing a knee arthroscopy on Wednesday.
Swans senior coach John Longmire hoped as recently as February that the big man would be available in the first six weeks of the season.
The 26-year-old played 28 games in three seasons after making his debut in Round 23, 2014, before rupturing the ACL in his right knee during the 2018 pre-season.
Naismith, who last played in Sydney's losing 2017 semi-final to Geelong, developed soreness in his right knee after his training intensity was increased.
Naismith will be temporarily sidelined and his return is unclear.
The news comes as Callum Sinclair and Aliir Aliir form a new ruck combination for the Swans' opening game of the season on Saturday night against the Western Bulldogs.
Sinclair, 29, competently filled in for Naismith for the 2018 season, averaging 29 hit outs per game, 14.6 disposals - 8.6 contested and kicked 12 goals.
The 200-cm ruckman joined the Swans in 2015 on a 4-year contract through the 2015 NAB AFL Trade Period, in a straight swap for speedster Lewis Jetta.
Aliir Aliir was trialed as a ruckman throughout the JLT Community Series and has been named to start the match as the Swans ruckman.
While lacking the body size to compete with bigger ruckman, his athleticism was a key feature in his ability to not only shark a hit out, but rove his opponents taps.
Another option for the Swans in Darcy Cameron, who debuted for the Swans last season in Round 17 against Gold Coast, picking up 3 disposals and 9 hit outs.
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