MLS teams seeking reinforcements, be they domestic or overseas, must act by Wednesday or wait until midsummer.

That's because 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, closes on Wednesday. Any such transaction not completed in time this week will have to wait until the opening of the secondary transfer window, which runs July 4 to August 3.

The final cutoff arrives at midnight CT (1 am ET) Thursday morning (on account of the US Soccer Federation's headquarters located in Chicago).

Teams can still make trades that do not involve players – that is: swap draft picks, roster spots, allocation money and other assets – outside the two windows. Clubs may also transfer or loan their players to non-MLS clubs at any time, subject to the transfer window of the recipient club's national federation and subject to the consent of the player.

The transfer windows – the dates between which MLS may request the international transfer certificate (ITC) of a player under contract in another country – are as follows:

Primary Transfer Window | Feb. 18 – May 11, 2016

Secondary Transfer Window | July 4 – Aug. 3, 2016

Full MLS roster rules and regulations