Roosters hit hard with injuries in loss to Rabbitohs

Sydney Roosters' season has been plunged into disarray with star half Luke Keary suffering a suspected season-ending ACL injury in Friday night's 26-16 NRL loss to a rampant South Sydney.

Keary went down without contact and clutched his left knee before being taken from the field shortly after halves partner Lachlan Lam suffered a suspected MCL injury.

The duo suffered the injuries in the second half at Stadium Australia adding further woe to the depleted Roosters who already have co-captains Jake Friend and Boyd Cordner on the sideline for concussion precautions.

It was a second-half massacre for the Roosters with prop Lindsay Collins taken from the field in a medicab after he was knocked out cold by friendly fire from teammate Jared Waerea-Hargreaves.

Coach Trent Robinson was devastated after the game, but said the halves injury crisis will open the door for replacements - most likely young gun half Sam Walker - to move into the NRL side.

"That's the wonderful part of our sport. It's really tough but let's go," he said. "Let's find a way... it's what you do.

"You get disappointed for five minutes and then you get excited for what's next.

"This is the acceleration of some other guys in our team to go and take opportunities and it's up to us to find a way... it's round three."

The injuries capped off a rotten night for the Tricolours after they were blown off the paddock in the first half by the Rabbitohs who led 24-0 early into the second half.

In the first two games of the season Brett Morris and James Tedesco had scored 11 tries between them but they were held to just one each on Friday night.

A try on the buzzer for Josh Morris made the scoreline respectable.

The ruthless energy that had dominated Manly and Wests Tigers arrived too late and the Rabbitohs had them rattled from the outset.

Former Roosters fullback Latrell Mitchell reminded them what what they're missing with a trick play to put Cody Walker over for the first try after eight minutes, with Dane Gagai crossing soon after to go ahead 12-0.

The Roosters were barely holding on at 14-0 when Daniel Suluka-Fifita's baffling brain explosion cost him 10 minutes in the bin, but he was lucky it wasn't a send off.

With tensions already bubbling, the 21-year-old prop let rip with a punch to the back of Jai Arrow's head while the Souths forward was held in a three-man tackle.

Josh Mansour scored soon after to hammer home the lesson and give Souths an 18-0 lead at the break, extended by Walker's second try early in the second half.

"We certainly owned the first half. The second half was a bit of a mess because of the situation with all the injuries, we just couldn't get momentum and everyone was standing around for too long," said Souths coach Wayne Bennett.

Poor execution cost the Roosters dearly, while Waerea-Hargreaves also gave away his fair share of penalties, copping Cameron Murray around the ears in the first half, and Mitchell on the nose in the 55th minute.

It all compounded for the Roosters in their first loss of the season, while the Rabbitohs are now two from three to start the year.