Canterbury second-rower Josh Jackson reckons he’s got some inside knowledge on the Sydney Roosters’ lethal left edge – but even that might not help him.

The Bulldogs face off against the Tricolours in the NRL’s first semi-final on Friday night, with the winner moving on to meet Brisbane for a place in the grand final.

The loser is consigned to another summer of what ifs.

Jackson lines up against NSW teammates Boyd Cordner, Michael Jennings and Daniel Tupou, who have scored a combined 30 NRL tries between them on their favoured left flank.

With the exception of Tupou, who only played in game one of the State of Origin series this year, Jackson played alongside both Cordner and Jennings for the entire campaign.

And while he admits that his time in Blues camp has given him the scoop on how the trio work, Jackson concedes it might not be enough.

“You know bits and pieces of their game. But it’s one thing knowing – it’s another thing stopping them,” he told AAP.

“Most of the teams in the NRL do a fair bit of video and know what’s coming, but stopping it is another thing. It’ll be a really tough one.”

Jackson pointed out that Jennings in particular has hit a purple patch of form that makes him one of the Roosters’ biggest threats this weekend.

The former Penrith centre unleashed his trademark acceleration in the second half to kickstart a movement against Melbourne that ended in Shaun Kenny-Dowall crossing for one of the tries of the season.

“Obviously they’re all quality players who have played for their country and state, and all played really well (against Melbourne),” Jackson said.

“But I thought Jennings was explosive. You give a guy like that too much opportunity with the ball and he’ll really hurt you.”

The Bulldogs suffered a huge blow on Monday after second-rower Frank Pritchard was handed a one-game ban for kneeing St George-Illawarra five-eighth Gareth Widdop on Saturday night.

The club has until midday on Tuesday to decide on whether to contest the charge.