The former ACT Brumbies and Wallabies winger signed a one-year deal with his old Super Rugby club this morning.

It is three years since he retired because of a chronic knee injury and six years since he last represented the Wallabies.

But Roff, who was teammates with Rathbone in the Brumbies' 2004 championship-winning team, had no doubt the South-African born player had the capacity to return to the top and play Test rugby.

''I would say unequivocally he can comeback,'' Roff said.

''Clyde has been hampered a little bit by injuries but he's a Wallabies winger who is still young enough and good enough to be returning to the Wallabies if he can stay fit.

''If he can stay fit and the Brumbies look after him I think he can really exceed his own and other people's expectations.''

Roff has spoken to club insiders who have revealed Rathbone's physical testing places him near the top of the current Brumbies squad in speed and strength.

Durability has always been Rathbone's limitation, but Roff said the 31-year-old was better equipped to address that.

''He's probably more mature and a bit more self-aware about looking after his own body as well,'' Roff said.

''For those who remember him playing, he was an incredibly confrontational, physical player. He would throw his body at brick walls. So it's just about being smarter about how he looks after his body.

''I've caught up with him a number of times, he's a good friend and he's got a real self-awareness of what works for him and what doesn't.''

''I hear he's nigh on the fastest in terms of his speed-testing. He's a freak of an athlete. When I first saw him he'd come in and warm-up on 180-kilogram squats as a young kid.

''He's exceptional. I remember seeing him for the first time and being blown away.

''I couldn't stop talking about the size of his quads and how powerful he is. He's just a freak athlete.''

Today's announcement will fittingly be made alongside Brumbies great Stephen Larkham, who contemplated his own comeback last season as the Brumbies faced an injury crisis to their playmakers.

But while Larkham only toyed with the idea, Rathbone is ready to re-enter the game after retiring because of injuries and then facing a personal battle with depression. Roff said Rathbone's presence would also add valued experience to a Brumbies squad which has developed promising outside backs such as Henry Speight, Joe Tomane, Jesse Mogg and Robbie Coleman.

''It's still a young side and the success they've had this year, he'll fit into that success and bring an added level of maturity and seniority to the direction the team's going,'' Roff said. ''It's a very potent mix of skill, experience and maturity that he has, but also add the quality of person he is … the senior guys have built something really special, it looks like a great environment to be a part of and he'll add to that.''

Coach Jake White hailed Rathbone's official return this morning as a sign the Brumbies were heading in the right direction.

‘‘It’s fantastic that a guy like Clyde can see the value of our rugby program and wants to come back and have another crack at playing professionally,’’ White said.

‘‘From the first time I saw Clyde play as a youngster, I knew there was something special about him and that I wanted a chance to coach him at a higher level.

‘‘From a coach’s perspective, Clyde’s signature is another confirmation that what we are doing with the Brumbies and rugby in the ACT is on track.

‘‘I look forward to seeing Clyde contribute to this team, both on and off the field, throughout the coming Super Rugby season.’’

Rathbone and White have previously worked together as captain and coach of South Africa’s under-21 world cup winning side in 2002.

with David Polikinghorne