Clifford was assessed a major penalty for boarding and a game misconduct just seven minutes into Game 1 for a hit on Ross Colton.
The Tampa forward was sent face-first into the glass, but escaped serious injury on the play.
The NHL’s department of player safety, which issued the suspension following a hearing with Clifford on Tuesday, described the incident in an explanation video as a “forceful hit to a defenceless player who is no longer in possession of the puck.”
The Leafs killed off the ensuing five-minute power play and opened the best-of-seven series with a 5-0 win over the two-time defending Stanley Cup champions.
Toronto head coach Sheldon Keefe said Tuesday before the suspension was announced that Clifford’s penalty put the Leafs in a tough spot.
“(Clifford’s) got to toe the line. And that’s not an easy ask for the player like him. When you’re him, you want to get on top of the opposition quickly, you want to finish your checks, you want to make your mark physically,” Keefe said. “He just finished a good check (on Lightning defenceman Jan Rutta) and the building’s kind of erupting. And then all sudden, there’s a second check there. It’s a split-second decision, and it wasn’t a good one for him. But he knows that.
“He’s been around the game a long time and has played that way a long time. He paid for it in that moment. We paid for it as a team.”
Clifford will miss Game 2 on Wednesday.
The NHL’s department of player safety also announced that Toronto forward Wayne Simmonds and Tampa Bay forwards Corey Perry and Patrick Maroon have each been fined US$2,250, the maximum allowable under the collective bargaining agreement, for unsportsmanlike conduct during Game 1.
The three players were instigators in a line brawl that erupted midway through the third period.
Maroon was assessed a 10-minute misconduct, while Perry received a minor penalty for unsportsmanlike conduct, a pair of minor penalties for roughing and a 10-minute misconduct. Simmonds was handed a 10-minute misconduct.