North Melbourne star defender Robbie Tarrant is set to miss a majority of the season after undergoing kidney surgery, per SEN's Sam Edmund.

Tarrant required surgery this week after a small mass was discovered on his kidney and is now expected to return in the second half of the season.

The 31-year-old has currently been battling a groin injury this season, which kept him out of the Kangaroos' Round 1 side.

North were defeated by Port Adelaide by 52 points at Marvel Stadium, with half-back Luke McDonald a late withdrawal from the match due to quad complaint.

The building casualty ward is placing a major strain on David Noble's defence, with tall defender Aidan Corr in doubt for this weekend's clash against Gold Coast.