Melbourne ruckman Max Gawn will have surgery on his injured hamstring, and will be sidelined for up to 12 weeks.

Gawn sustained the injury late in the first half against Geelong on Saturday afternoon, but initially thought the injury would see him sidelined for just one month.

Gawn spoke to the media on Monday afternoon, and said he would have surgery to repair the injured hamstring on Tuesday.

"There's a gap between the bone and the tendon so it's probably safer and quicker to get surgery," Gawn said.

"I'd say it's probably that three-month mark.

"I don't know anything about hamstrings or rehabbing them but I'd say around that 12-week mark."

The ruckman initially thought the injury was that of a regular hamstring strain, but scans over the weekend revealed tendon damage which will see Gawn go in for surgery.

"Early on you can get referred pain in the belly (of the hamstring)," Gawn said.

"The physios here treated it where the pain was in the middle of my hamstring and that's where they thought it was.

"They always had that shade of grey, just because of the history that I've had, that it might be something else so it was lucky we got the scan."