Bird rights,
Early Bird rights and
Non-Bird rights are all mechanisms that allow teams to go above the salary cap to retain their own players. Trades usually have no effect on those rights, but that’s not the case with players on one-year contracts. A team that acquires a player on a one-year deal via trade can’t use any form of Bird rights to re-sign that player the following offseason.
The player often stands to lose financially in such a case, so the NBA allows players on one-year contracts to block trades. Despite this, some players allow trades to go through anyway, as
Marreese Speights did last year when the Grizzlies sent him to the Cavaliers.