Roberts has won 24 caps but his next chance to add to that tally will now be the RBS 6 Nations in 2011.
"I picked up the injury during the second Test last summer," said Roberts.
"I've had a couple of MRI scans which didn't pick up the injury and it wasn't until the surgeon had a look with a camera into the joint that the full extent of the injury was diagnosed.
"I played through last season with a lot of pain in it so it's logical that I get it sorted as soon as possible.
"I'm disappointed to be missing more or less the first half of the season but I will use the time to rid my body of any niggles and come back to the field in good nick."