Ference, 5-11 and 189 pounds, went unpunished in the first period of Boston's 4-1 playoff win Wednesday night when he elbowed Grabovski in the head by the boards.
The five-foot-11, 183-pound Grabovski finished the game.
"I just remember a pretty hard hit to my head," the Belarusian forward told reporters Thursday before the ban was handed down.
The league called the hit reckless in ruling that Ference, after playing the puck in the corner, had lunged towards the oncoming Leaf, "extending his left arm and shoulder, picking Grabovski's head and making it the principal point of contact."
Ference was suspended three games in January 2012 for boarding New York Rangers defenceman Ryan McDonagh.
Boston coach Claude Julien, also speaking before news of the suspension, declined comment on the hit.
"The league looks after those things. That job doesn't belong to me so I'll leave it at that," he said. "I do have my view on it but certainly not a view I should be sharing right now."
Asked who he might insert into the lineup if Ference was suspended, Julien said: "We have lots of depth. I'm not worried about that."
Toronto coach Randy Carlyle also elected to stay mum Thursday, noting that he had learned a $10,000 lesson in the past about commenting on league matters and officiating. His wife wrote the cheque, he recalled
"I got the raspberries for opening my big mouth," said Carlyle.
After Game 1, the Toronto coach said the Ference hit was part of the "physicality" of the playoffs.
"It's a game that's made to be physical," he said. "You're allowed to hit people.
"To judge if it was offside, a bad hit, or a belligerent hit, that's not for me to judge. That's for people in the league to make those determinations."
Ference will miss Game 2 of the series on Saturday night.