Although the non-waiver trade deadline for Major League Baseball is on July 31 every year, players can still be traded after that date.
If a player is dealt after the July 31 deadline, that player is required to be put on waivers. Teams can expose their players to the revocable waiver wire starting in August.
Waivers is a permission that is granted for certain assignments of player contracts.
For trades coming after July 31 deadline, players must be offered to the other teams that are in reverse order of the standings, starting with teams in the same league having first priority.
Once a player is put on waivers, the team can keep the player, negotiate a trade with the claiming team or outright release the player.
If the claiming team completes the transaction, they assume the player's salary. Teams discussing trades have 48 hours to complete the deal.
A team usually places a player on waivers once; if they do it a second time, they are barred from pulling back the waiver.
If a player goes unclaimed after 48 hours, then he has "cleared" waivers. His team can then trade him, barring he has a no-trade clause or 10/5 rights.
Players traded after Aug. 31 at midnight ET and added to a team's roster are not eligible for the postseason.