North Melbourne were forced into making their tactical sub change in the opening quarter of Sunday's game after defender Griffin Logue sustained a knee injury just minutes into the Roos' clash with Geelong at Kardinia Park.

An attempted tackle on Cat Mitch Duncan left Logue in the hands of club trainers and he slowly made his way to the interchange before requiring further assessment.

The injury came in the opening 10 minutes of the first quarter, with North Melbourne soon pulling the trigger on their sub change, with Jack Ziebell brought into play in place of his fellow backman.

"Griffin's got a serious knee injury, but we're not certain what it is yet," coach Brett Ratten said after the loss.

"He'll go for scans and we'll have more then, but he's going to miss some footy."

The Roos then lost star midfielder and co-captain Jy Simpkin for the second half after the onballer sustained a concussion prior to the main break.

The failed head injury assessment will mean Simpkin is set to miss North Melbourne's Round 18 match against Hawthorn, with Logue to join him in missing the winnable encounter.

The pair of injuries followed a late change for Brett Ratten's side, who decided to manage rookie George Wardlaw for the game and replace him with Charlie Lazzaro.

Geelong WON BY 62 POINTS
GMHBA Stadium