Western Force star Richard Brown has joined the growing list of top flight players to be ruled out of the World Cup through injury.

Brown, who will undergo a shoulder reconstruction on Thursday, has joined Springbok lock Andries Bekker (calf/Achilles) and Scotland back Hugo Southwell (knee) as confirmed non-starters at the World Cup in New Zealand later this year.

Also on the doubtful list are Wallaby prop Benn Robinson (knee), Bok flank Juan Smith (Achilles), All Black back Israel Dagg (quadricep) and Wallaby wing  Drew Mitchell (ankle).

Brown, who opted to undergo shoulder surgery to ensure he is fully fit for the 2012 season and beyond, is expected to be able to return to team training in approximately four months.

He dislocated his right shoulder in the opening round of the 2010 season, but played on in the hope he could ride out the injury and put himself in the frame for selection to play for the Wallabies at the World Cup in New Zealand.

Brown's injury will reduce the Wallabies' back row stocks considerably, with Wycliff Palu racing the clock to return from a shoulder injury in time for the tournament.

No doubt Australian coach Robbie Deans will be hoping his remaining back row forwards survive the Tri-Nations campaign unscathed.

"I wanted to give myself every opportunity to play at the World Cup and I tried to push through it for as long as I could but the time has come where it's just not an option anymore," Brown said.

"It's disappointing but I need to get it done now to make sure I'm ready for next season and get back to playing my best," he added.

''I knew, when I hurt myself last year, it was going to be hard to make the World Cup. I knew I was going to have to push through to make it, but I couldn't push through it any more. I need the operation and that's it.

"It's best to have it now and get it over with to get ready for next season. I'm disappointed but that's life, I guess."

Wallaby coach Robbie Deans did not consider Brown for the Tri-Nations series because he was under an injury cloud.

However, he left the door open by saying he could still have made the World Cup if he recovered.

Brown had scans before the Wallabies named their extended 40-man Tri-Nations squad, but after consulting both the Force and Wallabies medical teams, decided that an operation was the best path.

Western Force Coach Richard Graham said Brown had done all he could to contribute to the team and put himself in a position to contest a place at the World Cup but knew surgery was going to be inevitable.

"It's certainly unfortunate that the injury has ruled Richard out of the World Cup, he had worked extremely hard over the past 17 months and was a strong performer for both the Western Force and the Wallabies during that time," said Graham.

''However, there was always going to come a point that he would need to have it done.

"He'll now have the required time to recover and build his fitness back to its peak ahead of next season,'' Graham added.