The Knights had already lost influential players Kalyn Ponga and Jayden Brailey to concussion and Tyson Frizell to an ankle injury when Saifiti hit Simpkin from marker in the 65th minute of Newcastle’s 14-12 win at Leichhardt Oval on Sunday.

As Simpkin ran against the grain, he was struck in the head by Saifiti’s shoulder and fell to the ground, apparently unconscious.

Simpkin was eventually able to walk from the field for a Head Injury Assessment (HIA) and did not return, given the match had only 15 minutes to run, which is the time required for an HIA.

Saifiti, who made his State of Origin debut for NSW last year, became the first player sent off this season but Newcastle held on for a gutsy victory with only 12 men on the park.

On Monday, the NRL match review committee categorised Saifiti’s hit as a grade-three reckless high tackle, the worst grading possible for the offence.

It marks the harshest charge handed down for a high tackle since Zane Tetevano challenged his grade-three reckless charge in the final round of the 2017 season.

Saifiti will miss five weeks with an early guilty plea, but risks six weeks on the sidelines if he unsuccessfully challenges his charge at the judiciary on Tuesday.

Wests Tigers second-rower Isaiah Papali’i is also facing a ban out of the match, for dangerous contact on Jack Johns.

The Tigers recruit will miss one match with an early guilty plea, or two if he unsuccessfully fights the charge.

Knights halfback Jackson Hastings has avoided suspension for the high shot that broke Tommy Talau’s nose and sparked a confrontation between the former teammates at full-time.

Hastings attempted to apologise to Talau on field but the Tigers centre pushed him away, leading former Knight David Klemmer to join the fracas.

Security and Knights’ head of football Peter Parr moved in to separate the rival players.

Hastings can accept a $1,800 fine for his grade-one careless high tackle.

Meanwhile, North Queensland fullback Scott Drinkwater has accepted his three-match ban for the shoulder charge that left Brisbane Broncos winger Corey Oates with a broken jaw.

Cowboys teammate Peta Hiku will also miss two matches after pleading guilty to a crusher tackle on Oates, leaving the Cowboys short on backline stocks for matches against the Warriors and Canterbury.

Dolphins hooker Jeremy Marshall-King has also taken a two-match suspension for his hip-drop tackle on Canberra’s Corey Horsburgh on Saturday.

Marshall-King will miss the Dolphins’ clash with the Knights and the first Brisbane derby against the Broncos.