The star centre, a Lion in 2009, underwent knee surgery in March and missed Wales' recent tour of Australia following a succession of injuries to his left knee.
Roberts was eventually forced to have an ACL reconstruction but his rehabilitation is going well and he is already lining up a return at the beginning of the season.
"I am hopefully looking at getting back by September and October," said Roberts.
"That is the target but you never know with these injuries - it could be sooner or later. I have been working hard with the rehab, so it's fingers crossed.
"I have done 11 weeks rehab now and I am probably another 12 to 13 weeks to go. It all depends about what happens when I start running, which will be in two weeks."
The powerful centre was a major part of Wales' march to the Grand Slam and was sorely missed Down Under.
The 2009 Lions Man of the Series admits it was difficult to watch Wales but is determined to help them secure an illusive southern hemisphere scalp in the autumn where Australia, Argentina, New Zealand and Samoa visit the Millennium Stadium.
"It has been hard watching, it has been heartbreaking especially when they have come that close," said Roberts.
"They deserved a win and that's what makes it so hard.
"The boys have played well and people have put in some really good performances. Go back a while and nobody would have given us hope of going within a point of Australia away from home.
"The fact we were so close is really encouraging and at the same time frustrating. I'm sure the guys will be gutted about not taking a scalp out there but it shows the improvement.
"It's just about the final step and hopefully we can do that in the autumn."