The Sydney Roosters are likely to be without Nat Butcher for a length of time, following an innocuous-looking knee injury sustained during Sunday's win over the St George Illawarra Dragons.

Butcher was caught in an awkward looking tackle during the second half of the contest, with a lengthy stoppage following for trainers to assess his knee.

The second rower, who has been promoted to the starting team in recent weeks due to Angus Crichton being out suspended, originally attempted to play on, but was quickly then brought off the field with the knee no good.

Scans later today will confirm the full extent of the injury, however, Butcher was unable to return for the remainder of the Roosters' victory, which included a Dragons' comeback either side of halftime, only to have the Roosters kick away to win comfortably.

It's understood Butcher's injury prognosis could well be a meniscus tear, leaving him on the sidelines for four to six weeks.

If confirmed, it could be a case of season over for Butcher with just two weeks of the regular season and finals to go. A six week return to play could see him line up for the grand final, while a four-week return to play would mean he is available for a semi-final, should the Roosters need to play in Week 2 of the finals.

Butcher's wasn't the only scare for the already injury-ravaged Roosters.

Centre Adam Keighran was taken from the field in the opening minutes with a head injury assessment, the backup option unable to return. It forced Sitli Tupouniua into the second row for the remainder of the contest.

Jared Waerea-Hargreaves was also caught in an incredibly distressing position at the end of the first half, with his legs bending in ways the human body is simply not supposed to.

It was feared he could have injured his leg in all manners, but amazingly, the Kiwi forward was able to get back to his feet and continue playing before turning in a performance of over 60 minutes.