Both players were dejected figures on the bench during Sunday's loss to the Sydney Roosters after sustaining injuries early in the physical clash.

Buttriss damaged his left ankle early in the first half of the match, while Thompson lasted just one hit-up before injuring his left knee.

The Canberra Times understands both players could miss up to four weeks through their injuries, adding to a growing injury ward at Raiders headquarters.

Dane Tilse, Scott Logan and Phil Graham all missed last Sunday's match against the Roosters, and the injuries to Thompson and Buttriss will hurt the Raiders forward pack.

Buttriss said he didn't think he'd done much damage to his ankle.

''I wasn't too sure what was wrong,'' Buttriss said.

''I thought I'd just rolled it so I kept playing on until the second half.

''I kept playing and towards the back end of the half it started to get sorer so I knew there was something wrong with it, and then as soon as it's cooled down at half-time it wasn't real good.''

Buttriss missed the side's recovery session yesterday morning, restricted to crutches and a moon boot on his left ankle.

He said the ankle was too sore to test yesterday.

''The doctor is still a bit undecided as to what is wrong,'' he said. ''I'll have scans tomorrow so I'll just have to wait and see then what it is.

''I'm very hopeful it's going to be all right it's too swollen to see what is wrong with it at the moment so I'll just have to wait and see what the scans bring up.''

Thompson spent more than an hour with the club's doctors and physio yesterday and was unavailable for comment.

In more positive news for the Raiders, Logan's ankle injury has healed quicker than expected and he should return to first grade this week.

The clash with Parramatta has become a crucial fixture for the Raiders, eager to move off the bottom of the NRL ladder.

But the team will need to return to its point-scoring ways after scoring just one try in the last two hours of football this season.

Raiders five-eighth Terry Campese said his side needed to work on converting the opportunities.

''We had a heap of possession but just couldn't capitalise and couldn't score any points our ends to sets weren't too good,'' Campese said.

SATURDAY

NRL round two: Parramatta Eels v Canberra Raiders at Parramatta Stadium, Saturday 7.30pm. TV time: Live on Fox Sports 2.