Marchand will be eligible to return on Dec. 8, when the Bruins face the Canucks again.
This marks the seventh suspension for Marchand in his 13-year NHL career. His most recent suspension came in January 2018, when he received five games for elbowing.
Sunday's incident occurred 1 minute, 8 seconds into the first period of the game, a 3-2 Bruins win. Marchand was not penalized on the play, and Ekman-Larsson was not injured.
"I thought it was two guys battling for a puck, got tangled up," Bruins coach Brad Cassidy told reporters on Sunday. "They'll have to decide. You see a lot of those in a game, they're typically along the boards more often than in the open ice, but I've seen a lot of it this year."
The NHL made it a point of emphasis for officials to crack down on cross-checking penalties this year, and many around the league believe it has led to an increase of slew-footing -- or dangerous trip -- penalties.
The NHL Department of Player Safety has historically punished repeat offenders, especially when the same offense is being repeated.
Marchand has been warned through the years by the department about slew-footing opponents. He was fined for slew-footing Pittsburgh Penguins defenseman Matt Niskanen in 2011. In 2015, he was suspended two games for a slew foot on New York Rangers center Derick Brassard on a play that was strikingly similar to the one involving Ekman-Larsson.
He also has been suspended and fined for clipping, the act of throwing the body across or below the knees of an opponent from any direction. All of this established a pattern of dangerous tripping plays by Marchand that led to the three-game ban, according to the NHL Department of Player Safety
According to collective bargaining agreement rules, Marchand will forfeit $91,875 in salary -- a sum calculated based on his annual average salary. That money will go to the Players' Emergency Assistance Fund. Marchand, 33, has a cap hit of $6.125 million this year.
ESPN's Greg Wyshynski contributed to this story.