COLLINGWOOD defender Tom Langdon's season is in doubt after having arthroscopic knee surgery late last week.
The 22-year-old has missed the majority of the year to nurse a right ankle injury he sustained against West Coast in round six.
Magpies football manager Neil Balme said Langdon would now face more time on the sidelines following his latest setback, but did not reveal an accurate timeframe on when the backman would return.
"That knee that he's had has been giving him some trouble, so he went and saw the surgeon last week," Balme told collingwoodfc.com.au on Monday evening.
"They decided to have arthroscopic surgery last Friday … they had to fix some problem with his medial meniscus and he'll miss something – certainly medium-term maybe even long-term to recover from that.
"We're pretty happy with the outcome of it, but unfortunately he won't play for a little while."
Langdon featured in five of the first six games of the season before succumbing to injury, and has played a total of 46 games for the Magpies.
In December last year, Langdon had surgery on the meniscus in his right knee after experiencing soreness.
Meanwhile, Magpies coach Nathan Buckley said forward Darcy Moore would be available for selection in Saturday night's clash against arch-rival Carlton provided he got through training.
"He hasn't proved his fitness yet so he'll train tomorrow and Thursday, and if he's fit, he'll play," Buckley told Fox Footy on Monday night.
"We think he'll play at senior level. We've been encouraged by what he's put forward (and) there would have to be extenuating circumstances for us not to think that he makes us a better side at senior level already."
Moore has missed the past month to recover from a fractured collarbone he suffered against the Western Bulldogs in round 10.