The 30-year-old went down untouched clutching his lower right leg in the 48th minute at the SCG and was soon after carted from the field.

No doubt in excruciating pain, Johnson gave the thumbs up to the crowd from the back of the medicab before reports emerged of the season-ending injury.

"He's clearly disappointed, he feels his season's over. You know when you've ruptured an Achilles," said Sharks coach John Morris.

"He said he felt that straight away.

"He's OK within himself, he's obviously very disappointed but I'm not sure until we get the scans and get it all confirmed."

Adding to the Sharks' injury woes, prop Royce Hunt also took a ride on the medicab in the second half with an expected ruptured patella tendon.

Josh Dugan was also taken off late with a knee injury.

With just one game left before the finals, losing Johnson - who leads the NRL with 22 try-assists this season - is a disaster for the Sharks who will not have a second chance in week one.

He added another to his tally on Saturday night, but the Sharks trailed 24-12 when he was taken from the field.

And while the Sharks' injury crisis dominated the second half, the opening 40 minutes was all about the Roosters.

It was a magical night for Mitch Aubusson who scored a brace in his 303rd NRL game for the club to become the most-capped player.

"That standing ovation as I came out is something I'll never forget and it was a really special moment in my career,'' Aubusson said.

"It's been a really tough year for my family and myself. The club have rallied around me and given me the time I've needed and welcomed me back with open arms.

"A lot of my best mates are here tonight, my two kids, my wife, my mum and my brothers. I'm proud they can all be together.

"I definitely think the old man was looking after me tonight, for sure.''

Aubusson's father Brian unexpectedly passed away in May. He was only 60.

The first of his two tries came just five minutes after Aubusson led the team out as captain through a guard of honour before the second came later in the half.

It landed the milestone man his double and put the Roosters ahead 24-6 before they conceded late in the half.

After seven first-half errors the Sharks still managed to score twice with just 42 per cent possession steered around by Johnson who was in slick touch before he went down.

Ronaldo Mulitalo and Siosifa Talakai scored in the first half but a third try to Braden Hamlin-Uele further punished the disjointed Roosters' defence.

However, the premiers had enough class to polish off the win - even while missing some of their biggest stars.

James Tedesco, Jake Friend, Sio Siua Taukeiaho and Boyd Cordner all watched from the stands as the Roosters ran in six tries, including a double to Luke Keary.

Manu was binned late after repeated ruck infringements but the fullback also got on the board along with winger Daniel Tupou.

Meanwhile, the finals-bound Sharks side are already missing Matt Moylan, Wade Graham and Chad Townsend - the latter two through suspension.

Graham is set to return against Canberra next weekend.

Australian Associated Press