The Flyers will send New York a pair of future draft choices, a third-rounder in 2014 and a 2015 second-round pick, as well as minor league forward Matt Mangene in exchange for MacDonald, the NHL's leader in blocked shots (198) this season.
MacDonald has served as a mainstay along the Islanders' blueline over the past five seasons and is on pace to set a career-best in points in 2013-14, having recorded four goals and 20 assists in 63 games. The 27-year-old led New York and ranks eighth in the league in average ice time per game (25:25), and has averaged 20 or minutes per contest in each of his five full NHL seasons.
The Nova Scotia native, who is scheduled to be an unrestricted free agent at the conclusion of the season, has amassed 17 goals and 72 assists in 295 career games -- all with the Islanders.
Currently residing in 14th place in the Eastern Conference, the Islanders are expected to be one of the more active sellers up until Wednesday's trade deadline.
Mangene, a Long Island native, had three goals and three assists in 51 games for Adirondack of the American Hockey League.