A straight swap between Montreal and Philadelphia sees the former first overall draft pick heading home to Pennsylvania and last year's MLS All-Star moving to Quebec.
McInerney, 21, has been hot and cold with the Philadelphia Union, while still managing to lead the team in scoring over the last two seasons with eight and 12 goals respectively.
Impact sporting director Nick De Santis feels McInerney will be a good fit in Montreal.
"We are extremely pleased to be able to bring in a player of Jack McInerney's quality," De Santis said in club press release. "At a young age, he's already showed the ability to score goals in this league and we feel his qualities and soccer sense fit well within our style of play."
After being drafted first overall in the 2012 MLS SuperDraft, Wenger, 23, never lived up to his promise in Montreal, scoring a meager six goals in 51 appearances.
McInerney is expected to arrive in Montreal early next week.
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