South Sydney skipper Roy Asotasi will miss the remainder of the NRL season after suffering a torn anterior cruciate ligament in his side's vital victory over Manly on Saturday night.

Asotasi suffered the injury to his right knee in the 65th minute of the Rabbitohs' commanding 36-22 victory over the defending premiers when he fell awkwardly in a tackle.

The 27-year-old faces at least six months on the sidelines leaving him in a race against time to be fit for the start of the 2010 campaign.

He will also miss New Zealand's Four Nations campaign against Australia, England and France starting in October.

"It disappointing," a downcast Asotasi told reporters after the clash.

"I found out from the doc that it was an anterior cruciate but from the moment I took that run and got into that tackle I kind of felt something was a bit different in the knee area."

"I just felt my knee go outwards so, it just didn't feel right."

The injury is a bitter blow for the former New Zealand captain who missed last year's World Cup campaign with a pectoral injury suffered late in the 2008 season.

"I'm not having any luck in the last two years so I guess I'm going to have to start all over again," he said.

"I guess the only good news is that I'll be alright for next year, the only disappointment is I can't be with the boys as they march for the finals."

Rabbitohs coach Jason Taylor concedes Asotasi's injury soured the win over the Sea Eagles.

"Roy's done his ACL so he'll be out for the season so that's enormously sobering for the whole night, for the club and all of us - we're very disappointed for him," Taylor said.

"He's our captain and he's such an integral part of what we're doing, his performance in the first half tonight is what got us the victory and then to have that happen to him is very upsetting."

The Bunnies' ninth win of the season lifts them to within a point of the top-eight with four rounds remaining.

And Asotasi is adamant his absence does not signal the end of the club's finals hopes.

"We've got some depth in the club, you've got Scott Geddes who did a terrific job tonight and I reckon he's the perfect guy to take over my position," he said.

"It's a team sport, I don't think one player will make a difference."

Key playmaker John Sutton agreed: "I reckon the boys will be still confident (of finishing inside the top eight). Losing Roy's a big loss but I think we've got the team to make the semis, so hopefully we just keep on winning."