Captain Andrew Swallow has needed surgery on a broken thumb, weakening North Melbourne for Saturday night’s AFL match against unbeaten Fremantle.

The star midfielder said he suffered a “whack” on his right hand in the second term of last Friday night’s win over Essendon.

The hand started swelling up and the thumb gave way early in the third term.

Swallow was able to play out the match, but Monday’s operation was an unpleasant surprise.

He hopes to only miss this weekend’s match.

“We thought I might have a little crack, but nothing major … it would be fine to play with and keep going,” Swallow told the club website.

“So I was a bit shocked in the end to find out within an hour and a half, two hours, that I was booked into hospital.

Swallow said it was a minor procedure, with the fractured bone straightened and a plate inserted.

“Hopefully, it should be right to go in a week or two,” he said.

“It looks a lot worse than what it is.

“It’s feeling pretty good, I just have to wait for a bit of the swelling to go down.”

The WA native said missing out on the trip west means more bad news for his parents.

Last weekend, his younger brother David was also not in the Gold Coast team that lost heavily to West Coast in Perth.