The Flyers announced a six-year contract worth $30 million US for MacDonald on Tuesday, a deal which runs through 2019-20. The pact represents a massive raise for a player who's never earned more than $600,000 in a season.
The Flyers obtained MacDonald from the New York Islanders before the trade deadline for a third-round pick in the 2014 NHL draft, a second-round pick in the 2015 draft, and minor league forward Matt Mangene.
The Judique, N.S., native played junior hockey with Cape Breton and has gone on to score 17 goals with 76 assists in 314 regular-season games in his NHL career, with 155 penalty minutes.
He led the NHL this season with 242 blocked shots.
Philadelphia returns to the playoffs after a one-year absence, visiting the New York Rangers for Game 1 of a Metropolitan Division series on Thursday.