Sixes and sevens ... Sam Williams and Terry Campese.

Sam Williams with Terry Campese. Photo: Richard Briggs

Canberra halfback Sam Williams could be the player to benefit most from Josh Papalii's defection to Parramatta.

The 21-year-old is off contract at the end of this season, and the Raiders are yet to open official negotiations with the highly rated halfback's management.

Williams is virtually guaranteed a first-grade spot for the opening five rounds because chief playmaker Terry Campese is sidelined with a knee injury. While it gives Williams an ideal chance to prove himself, his value on the open market would also increase if he enjoys a strong start to the season.

The likes of Penrith and St George Illawarra expressed interest in the Cooma player late last year, and the Raiders are desperate to retain him.

Papalii has signed a three-year deal with the Eels believed to be worth about $500,000 a season, starting next year.

Canberra will fight hard to change his mind before the round-13 deadline, but should he leave it frees up more cash to keep Williams.

Centre Jarrod Croker, second-rower Joel Thompson and prop Brett White head a long list of Raiders off contract at the end of this season.

In terrible conditions, Williams looked sharp in Canberra's 22-18 trial win over Canterbury at Goulburn on Saturday night.

Five-eighth Josh McCrone was outstanding, and his understanding with Williams has developed nicely after playing nearly two seasons together.

''All good young halfbacks are in demand, and we certainly plan to keep him and he is in our plans,'' Raiders chief executive Don Furner said. ''There's options for them, Josh [McCrone] could play nine, Campo could play lock but that's up to the coaches, I don't get involved in that.''

The Raiders are frustrated the salary cap, expected to increase by $700,000 to $5 million this season, wasn't resolved far earlier.

They believe Papalii would have re-signed in December, robbing Parramatta of a chance to target him after missing out on Cowboys props Matt Scott and James Tamou.

''Before Christmas [we would have re-signed him] probably. It's frustrating, but we'll see,'' Furner said.

''It's always a balancing act. Guys like Sammy, Crokes and Joel Thompson, there's some younger guys as well [to try and re-sign].''

Furner conceded Canberra may have to shed one or two players if they decide to increase their offer to Papalii.

Papalii brushed aside the drama to perform strongly against the Bulldogs, and Williams doesn't expect that to change once the season begins. ''He's the ultimate professional, Papa, he always does his job and puts 110 per cent in,'' he said.

''Whatever happens, happens, as long as he's playing well. We'll stay together and stay tight and back each other, and worry about that stuff come the middle of the week.''