Former England Under-21 international Hobson was cited following the incident in a Guinness Premiership game between Bristol and Wasps at Adams Park nine days ago.
Vickery suffered concussion as a result, which ruled him out of the 26-18 victory over France last weekend in addition to this Saturday's RBS 6 Nations finale against Wales in Cardiff.
Hobson had already received a two-week suspension from his club following an internal disciplinary hearing.
But a complaint was lodged against him by the independent citing commissioner, and he appeared before a Rugby Football Union disciplinary panel in London today.
Hobson's ban will rule him out of action until March 26.
London Irish full-back Delon Armitage has received a one-week ban after being sent off for striking an opponent during last Saturday's Guinness Premiership victory over Bristol.
Armitage, who appeared before a three-man RFU panel, will miss Irish's home Premiership clash against Wasps on Sunday.