North Melbourne key defender Nathan Grima says his light-hearted approach to football has been tested by a horror run of injuries.

Grima had surgery on Wednesday to remove a section of damaged disc from his back.

The Tasmanian had surgery on the same area of his back in late 2010, but the disc problem has flared from time to time since.

Grima has also been plagued by knee problems, after undergoing an anterior cruciate ligament reconstruction before he had played an AFL game, while his 2014 season was plagued by a navicular injury.

In seven seasons at North, he has played just 86 games despite being an almost automatic senior selection since 2010 when fit.

Grima has made a name for himself off the field in recent seasons with his quick wit, enjoying regular spots on radio and television.

Speaking from his hospital bed at Melbourne's Epworth Hospital on Thursday, Grima told SEN radio his latest surgery had been no laughing matter.

"I often get criticised for taking the game so lightly and laughing, but I can tell you this is the ninth surgery I've had and when you're lying in bed and pretty sore it takes the gloss off footy," Grima said.

"But everyone goes through it."

North football director Geoff Walsh said on Tuesday that Grima would be sidelined for about 12-14 weeks.

"The docs have had a round-table conference on this, and it's been decided there will be surgery," Walsh said.

"It hadn't been responding to the conservative treatments."

Grima, 29, is set to come out of contract at the end of this season.