Speight was shown a red card for slamming Juan de Jongh head-first into the ground at a ruck in the 74th minute of the Canberra-based outfit's stunning victory over South Africa's Stormers last weekend.
The Wallabies winger had already been found guilty of the offence by a judicial hearing but the Brumbies were given a glimmer of hope that he might escape a ban when officials requested more information before handing down the punishment.
“After taking all relevant facts into consideration, I found that the referee's decision to issue a red card was correct,” the judicial officer said in his decision.
“The tackle caused De Jongh's feet to lift and his head to make contact with the ground first.
“It was not a legitimate clean out at a ruck and the player was fortunate not to have been injured.
“An aggravating factor is the ongoing need for a deterrent for dangerous play such as this which carries with it the real risk of serious injury.”
Speight's ban means he will also miss Australia's opening match of the Rugby Championship against South Africa in Brisbane on July 18.
Brumbies prop Scott Sio said the team would undoubtedly miss the hulking Fiji-born winger.
“Especially with the calibre of player he is, he adds such a lot to the team, not just in attack but in his defensive awareness as well,” he told reporters in Canberra before the verdict was announced.
“We lose a lot there, but the best thing about our squad is that we've got guys like Robbie Coleman, James Dargaville, Nigel Ah Wong, Lausii Taliauli, who all add something different if they are called upon to replace Henry.”
With their other winger Joe Tomane on fire after a hat-trick against the Stormers last week, it is in defence that the Brumbies will miss Speight most.
If Speight had escaped a ban, he would have been responsible for marking All Blacks left winger Julian “The Bus” Savea on Saturday.
Coleman would be the most obvious replacement on the right wing but while the 24-year-old has no shortage of pace, he gives up 20 kg in weight and 14 cm in height to Savea. – Reuters
Original source: Dangerous play costs Brumbies winger