Bulldogs back-rower Josh Jackson.

Bulldogs skipper Josh Jackson is free to lead his side against North Queensland after successfully disputing the grading of his heavy shot on Canberra's Aidan Sezer.

Jackson's hit on Sezer as the Raiders half kicked downfield last weekend was downgraded by the judiciary on Tuesday evening, with Canterbury's gamble to challenge the original grade two charge paying off in spades.

Having lodged a guilty plea to the reduced grade one charge, the 75 demerit points and Jackson's clean record have cleared him for Saturday night's crucial trip to Townsville.

It's a critical boost for the struggling Canterbury outfit given both they and the Cowboys have started the year with an underwhelming 1-4 record.

Jackson cleaned up Sezer with just three minutes to go in a 24-6 loss in round five, but the star second-rower denied he let his frustrations get the better of him with his late tackle.

"It was just a tackle that went wrong," Jackson said afterwards.

"It could seem like that with the stage that the game was at but it was just the fact that I was trying to put on a bit of kick pressure.

"I didn't swing my arm or anything like that, so there was certainly no malice or anything like that involved."

Bulldogs captain Josh Jackson.
Bulldogs captain Josh Jackson. ©Gregg Porteous/NRL Photos

Over the course of a half hour judiciary hearing, both the NRL and Jackson's defence cited a grade one dangerous contact charge levelled against Newcastle's Mitch Barnett for a late, high tackle on Wests Tigers Luke Brooks last year.

Barnett was free to play following an early guilty plea to that charge, with Jackson's lawyer Nicholas Gabbar successfully arguing that "a number of factors made Barnett's tackle significantly worse" than that of the Bulldogs back-rower.

Gabbar contended that Jackson had hit Sezer first on his torso before making contact with the No.7's head, and only "marginally late" in comparison to Barnett's hit, with a drop in Sezer's body height also contributing to Jackson's high contact.

The three-man panel of Sean Garlick, Tony Puletua and Bob Lindner took less than five minutes to downgrade the charge. A failed challenge would have rubbed Jackson out of both this week’s clash with the Cowboys and a round seven bout with the Roosters at ANZ Stadium.

Despite being forced from the field Sezer pulled up fine from the tackle and will take his place for the Raiders this Saturday against Parramatta at GIO Stadium.

Jackson meanwhile will be expected again to make a beeline for veteran Cowboys skipper and chief playmaker Johnathan Thurston, who has copped plenty of heavy hitting himself across the start of 2018.