Carlton star Charlie Curnow faces up to a two month delay to his originally slated January return date, reports AFL Media's Riley Beveridge.
The 23-year old has reportedly had successful surgery last Wednesday for a stress injury to the patella in his right knee.
The Blues are hopeful that the forward will return to running after Christmas following his latest setback, but will understandably play it ultra cautiously.
The club will see how he responds to rehab before ramping up his training load after the new year.
It puts Curnow in serious doubt for Round 1, who missed the last eight games of the 2019 season and entire 2020 campaign due to a recurring knee injury.
The athletic big man had reportedly been training the house down in Carlton's last few weeks in the Queensland hub.
However, he fractured his knee cap while kicking the footy with brother Ed earlier this month.
Curnow has kicked 77 goals from 58 AFL games since making his debut in 2016.