The non-waiver trade deadline, which almost always falls at 4 p.m. ET on July 31, is the last point during the regular season at which players can be traded from one club to another without first needing to clear waivers. Following the passing of the deadline, players on the 40-man roster must first clear revocable trade waivers in order to be traded to another organization, thereby greatly reducing the ability for clubs to gauge the asking price of movable assets and, subsequently, reducing the number of trades.
Major League Baseball set the 2016 non-waiver trade deadline for Monday, Aug. 1., in order to avoid having the deadline fall in the middle of the schedule of day games on Sunday, July 31. Pushing the deadline back one day to Aug. 1 -- when no games are scheduled to begin before 7 p.m. ET -- prevented players from being traded in the midst of active games.
Aug. 31 postseason roster deadline
The last day in August is sometimes referred to as the "waiver trade deadline," as players acquired after that date are ineligible to be added to the postseason roster by their new teams.
Aug. 31 is not a firm deadline for trades, however, as players can still be dealt after that date. For instance: On Sept. 13, 2015, the Blue Jays acquired infielder Darwin Barney from the Dodgers. But because Barney was acquired after Aug. 31, he was ineligible for the postseason roster and did not appear with Toronto in either the ALDS vs. the Rangers or the ALCS vs. the Royals.
Non-Waiver Trade Deadline Example
Shortly before 4 p.m. ET on July 31, 2015, the Mets acquired outfielder Yoenis Cespedes from the Tigers in exchange for Minor League pitchers Michael Fulmer and Luis Cessa. Cespedes went on to bat .287/.337/.604 with 17 home runs in 57 games for the Mets, who ended up winning the National League East as well as the NL pennant.