COLLINGWOOD has suffered another pre-season blow with midfielder Levi Greenwood undergoing left knee surgery on Tuesday.

He is expected to be out of training until late January.

Greenwood sprained his medial ligament in round 20 as the Magpies beat North Melbourne, and he missed the final three matches.

The club used external advice to decide on rest, rather than opting for post-season surgery.

Greenwood, 28, had trained throughout the pre-season but felt pain in his knee.

"The surgery, to the medial ligament, is relatively minor, but it should allow Levi to fully recover and play and train pain free. We expect him to be back running inside six weeks," football manager Geoff Walsh told collingwoodfc.com.au.

Greenwood's tagging was important in a season in which he played 16 games.

His situation is similar to that of forward Jamie Elliott, who will be in rehab until at least March after having a left ankle operation in November.

He too was expected to heal with rest, before eventually needing to go under the knife.

"That's one thing about Jamie – his approach to his rehab is pretty strong and he's doing the same thing again," Walsh told Melbourne radio station SEN recently.

"So while that is (still) a 12, 14-week stint on the sidelines, he's really pleasing our medical people with his progress."

Alex Fasolo will not be back until February after recent shoulder surgery while captain Scott Pendlebury had surgery last month to have pins removed from his right middle finger, which were inserted following an injury suffered against Gold Coast in July.