Trade Waivers & Aug. 31 'Deadline'
Before 2019, players could be traded following the Trade Deadline (prior to the 2022-2026 collective bargaining agreement, the Trade Deadline almost always fell on July 31 at 4 p.m. ET, but the Commissioner's Office now has the flexibility to set the Trade Deadline on a date between July 28 and Aug. 3) if they first cleared revocable trade waivers.
Although trades could still be completed after Aug. 31 as well, players acquired after that date were ineligible to be added to the postseason roster by their new teams. As a result, the last day in August was sometimes colloquially referred to as the "waiver Trade Deadline."
Under the old system, the player's original club had three options when a trade waiver claim was placed: It could either work out a standard trade with the claiming club (the two sides had 48 hours to agree to a deal), allow the player -- and all money remaining on his contract -- to go to the claiming club with no return or pull the player back off waivers. A player who was pulled back off waivers could be placed on trade waivers a second time, but at that point the waiver request became irrevocable. If a player passed through waivers unclaimed, he could then be traded to any club, free of restriction (though all 40-man-roster players in the trade had to clear waivers before being dealt).
As of 2019, players may still be placed and claimed on outright waivers after the Trade Deadline, but trades aren't permitted after that date. With regards to newly acquired players, the Aug. 31 postseason roster deadline remains in effect.