A devastated Cooper Vuna has vowed to again bounce back after suffering a fractured shoulder that will keep him out of the Melbourne Rebels side for the first four rounds of the Super Rugby competition.

The 25-year-old winger said he had "trained the house down" to be ready for the season kick-off against the Western Force on February 15 at AAMI Park after undergoing a reconstruction on his other shoulder in August last year.

He made the choice to have that surgery in order to be fit for the Rebels' opener, when he could have delayed it and added to his two Wallabies caps.

During the pre-season he dropped a staggering 10 kilograms to get down to 102kg and was flying in training and although the fractured scapula won't require surgery, it's still a setback.

"I've done everything in the pre-season and done everything right with my shoulder rehab so to do the other shoulder, it's not ideal," the former rugby league player said.

"It could be worse but it's still a long time."

Vuna said he was excited about getting back on the field in a new-look Melbourne backline following the departure of veterans Stirling Mortlock, Mark Gerrard and Julian Huxley.

"I was in good shape and where I wanted to be in terms of training so I'll have to start all over again.

"Next week I'll meet with the conditioning coach and try to get on top of it again."

Vuna has played in 29 of a possible 32 Super games and has been the club's leading tryscorer in its two years in the competition.

He earned his two Wallaby Test caps in June against Wales and after getting a taste is eager for more.

Wallabies coach Robbie Deans had been in touch after his latest injury to check on the prognosis.

The injury is another blow to the depth of the Melbourne backs after losing highly-rated Kiwi fullback Jason Woodward, who is out for five weeks after surgery on a finger tendon.

Rebels coach Damien Hill believed they could cover the loss.

"It's a big disappointment for the team," Hill said.

"Cooper has had a great pre-season and we could have done without this hurdle.

"On the positive side we have a number of first year players that impressed in our first trial and one of them will now get an opportunity sooner than they may have expected."

The Rebels play their final trial against the Wellington Hurricanes this Saturday at 5:30pm (AEDT) at Simonds Stadium in Geelong.

- AAP