Wood, who suffered a hamstring injury at training in February, will miss at least another three weeks of football.
“Mason was cleared to play in a VFL practice match on the weekend but felt some pain in his knee,” Roos General Manager of Football Cameron Joyce said.
“Scans revealed a tiny bone fragment floating in his knee joint that was unrelated to the previous hamstring injury. As a result, Mason underwent a minor arthroscope on Tuesday to wash it out.”
In some positive news for North Melbourne, Ben Brown and Majak Daw, who both pulled up sore after the weekend’s one-point loss to Geelong, have been cleared to play this week against Greater Western Sydney.