Baker, who played on the left wing for the Highlanders last Friday night in the 33-30 win over the Rebels at Forsyth Barr Stadium, was cited after the game for a clean-out at a ruck in the 11th minute of the match.
Though the incident was missed by the referee, it was seen by the Sanzar citing commissioner watching the match.
It was ruled, after review of the match footage, that the incident had met the red card threshold for foul play.
The incident occurred as part of a Highlanders attacking movement which ended with Aaron Smith running over the line and thinking he had scored. The try was ruled out because of a forward pass.
As part of the movement into Smith's disallowed try, a breakdown occurred where Baker entered and cleaned out Rebels halfback Nic Stirzaker.
The clean-out involved Baker lifting Stirzaker off his feet into a vertical position, with the halfback landing on his head. Stirzaker was not injured and continued playing in the match.
If Baker pleads guilty at the hearing, which he is expected to do, he will get a minimum suspension of four weeks, possibly more.
The decision should be released today.
Baker only played on Friday night as regular winger Patrick Osborne had been struggling with an ankle injury earlier in the week.
But Osborne played club rugby for Green Island on Saturday and should be right for the match against the Bulls.
This match looms as an important game for the Highlanders.
The Highlanders sit in 10th position with the Bulls in seventh spot, just two points in front of the southern franchise.
The four teams directly above the Highlanders have all played one game more and two of them - Blues and Hurricanes - have the bye this week. No points are awarded for a bye.
A win on Friday night will give the Highlanders a real boost going into a bye week and then a trip to South Africa.
The Bulls will limp into town having suffered some injuries in their close 25-20 loss to the Hurricanes in Napier on Saturday night, although the injuries do have something of a silver lining.
Bulls loose forwards Deon Stegmann and Dewald Potgieter are already heading home to South Africa, Stegmann having injured his groin and Potgieter a biceps.
Stegmann has been replaced by Wimpie van der Walt.
Veteran lock Victor Matfield, who came out of retirement this season to play, was not expected to play on tour, but still travelled with the team.
Grant Hattingh, who is with the touring squad, will move from lock to the loose forwards and Matfield has been added to the playing squad. Matfield's experience is a shot in the arm for the Bulls, who are bound to be very confrontational on Friday night.
In other games at the weekend: the Blues lost to the Brumbies 26-9, the Force beat the Reds 32-29, while in South Africa the Cheetahs and Chiefs drew 43-43, the Crusaders beat the Lions 28-7 and the Waratahs beat the Stormers 22-11.
