[MLS TRANSACTIONS] Wednesday marked the opening of the North America summer transfer window, meaning MLS clubs are free to sign players from overseas or activate players signed in the spring. Italian Marco Di Vaio finally made his debut for the Montreal Impact in its 3-0 loss to Toronto FC, while Honduran international Oscar Boniek Garcia is free to play for the Houston Dynamo, which signed him as a Designated Player. Meanwhile, the Columbus Crew and Chicago Fire, which both activated foreign signings, and the New England Revolution, which is looking to bring in new players, did some major housecleaning.

-- The Crew released three defenders: Jamaican Shaun Francis (28 appearances in three seasons), Korey Veeder and rookie Aubrey Perry.

Costa Rican forward Jairo Arrieta, signed in April from Saprissa, is now eligible to play for the Crew, which is looking for help at left back.

-- Alex, a 23-year-old Brazilian midfielder signed from Swiss team FC Wohlen in April, became eligible to play for the Fire, which sent defender Kwame Watson-Siriboe to Real Salt Lake for a draft pick.

Chicago also waived Zimbabwean international Kheli Dube, who didn't make an appearance for the Fire after playing 72 MLS games in four seasons with the Revs.

-- The Revs waived Colombian central defender John Lozano and declined the July 1 contract options due on Swedish forward Bjorn Runstrom and midfielder Jeremiah White.

“With the International Transfer Window opening," New England general manager Michael Burns said, "we had to make some hard decisions about our roster as we look to bring in some new players.”