It's a frightening prospect that will send chills through opposition camps before Thursday night's NRL season start.

As if the Sydney Roosters weren't already looming as benchmarks once again with a raft of big guns finally back to full health, now superstar skipper James Tedesco has declared himself feeling better than ever before.

The lightning No.1 underwent stem cell surgery on his left knee during the off-season, when doctors mixed fat and blood and injected it to strengthen his leg.

Now Tedesco feels like he's running on two fit legs for the first time in years.

"I've been hurting after games and just getting through," the Roosters and NSW State of Origin captain said.

"The rehab we've been doing and the program I've had during this pre-season has been really good.

"I feel stronger than ever and the body feels really good as well.

"It's a great start to the season."

Look out if the 2019 Dally M Medallist can reprise -- or eclipse -- his career-best form this season.

"A fully fit James Tedesco is a dangerous one," Roosters recruit Kevin Naiqama said on Monday.

After their annus horribilis last year, when repeated concussions forced co-captains Boyd Cordner and Jake Friend into premature retirement and other key figures dropped like flies, the Roosters shape as powerhouses once more.

Playmaker Luke Keary and Queensland Origin forward Lindsay Collins both return after missing most of 2021 with ACL tears, while injuries and suspension consigned Victor Radley and Sam Verrills to bit-part roles.

"The experience we can take away from last season and adding some of those really key guys back in Keary and Lindsay Collins will be a massive lift for us," Roosters and Blues back-rower Angus Crichton said.

In a huge boost, Crichton, himself fully fit after off-season elbow surgery, said he'd be betting on Keary to be lining up in round one against Newcastle on Saturday.

"We just need to get the team healthy and we'll be right," Tedesco said.

"But it takes a bit more than that. We've showed that during pre-season.

"We've worked really hard. There have been no complaints, no excuses.

"A lot of our young guys from last year got that experience out there. They're even more ready for first grade.

"We have a lot of healthy guys coming back, as well.

"It's definitely a big positive for us going into the start of the year."