Collingwood have suffered another pre-season setback with important onballer Levi Greenwood undergoing knee surgery on Tuesday.

He joins key Magpies Jamie Elliott (ankle) and Alex Fasolo (shoulder) on the sidelines after they also required surgery.

Greenwood was injured in the round 20 match against North Melbourne. Credit:AAP

The 28-year-old missed the last three games of last season with the injury that he suffered in the round 20 win over old side North Melbourne.

It was expected to heal with rest, but he complained of ongoing soreness as he participated in pre-season training and was sent for an operation to repair a damaged medial ligament.