Canterbury are facing an enormous battle to avoid the wooden spoon with key forward Luke Thompson suspended for three weeks on Tuesday night.
The English enforcer unsuccessfully challenged a grade-two dangerous contact charge for a late hit on Sharks hooker Blayke Brailey.
After announcing the guilty verdict, the judiciary panel of Ben Creagh, Bob Lindner and Dallas Johnson – who all appeared via video link – decided against a downgrade that would have reduced the penalty to a fine.
The 26-year-old will miss this weekend's clash with the Titans plus matches against the Wests Tigers and Warriors.
He could have accepted a two-match ban with an early guilty plea but will now serve an extra week as well as incurring 40 carryover points.
Thompson was sin-binned for the tackle, which Andrew Johns branded a "real cheap shot" in commentary, during the first half of Sunday's 44-24 loss at Cbus Super Stadium.
The particulars of the charge stated that Thompson had made dangerous contact with his shoulder and arms – something his lawyer Nick Ghabar disputed.
Thompson on report and sent to the sin bin for late hit on Brailey
He claimed that Thompson's torso and chest "clearly" and "largely" struck Brailey.
"It's frontal contact where a small man, having passed the ball, collides with a bigger man and, naturally, the force involved causes the smaller man to lose his balance and fall to the ground … exaggerating the significance of the impact," Ghabar said.
Ghabar added: "You're left to wonder: what is dangerous about the contact?"
Although he admitted there was "marginally late" contact, Ghabar argued that Thompson braced himself to "lessen the blow" and that a collision was "unavoidable".
But NRL prosecutor Peter McGrath described Thompson's conduct as careless and said he had "ample time" to decide against a "body-check".
"You can see the degree of whiplash that is caused by the impact," McGrath said as he submitted there was a significant risk of injury.
Comparable incidents from this season were shown to the panel before they upheld the original charge.
While the last-placed Bulldogs are officially out of playoffs contention, they have plenty of motivation as they fight to rise from the foot of the ladder.
With six games to go in the regular season, coach Trent Barrett's team are four points behind the Broncos and have a poorer differential.
Thompson will be sorely missed considering his sensational form. He racked up 204 metres, a try and 32 tackles against Cronulla.
The former St Helens prop hasn't had much luck at the NRL judiciary after last year copping a four-match ban – which carried into this season – for eye gouging James Tamou.
