Major League Soccer's primary transfer window, one of two periods on the calendar in which teams can register new players via international transfers or intra-league trades, officially opened on Tuesday.
Any transactions not completed during the primary transfer window will have to wait until the opening of the secondary transfer window, which runs July 10 to August 9 this year.
Teams can announce incoming transfers and trades outside of the transfer windows whenever the paperwork is official, but a player cannot officially be put on a club's roster until his International Transfer Certificate (ITC) is transferred, which must happen within one of the two transfer windows.