The Orioles received cash or a player to be named later. They also called up Chad Moeller from Triple-A Norfolk on Friday to take Zaun's place on the roster.
The switch-hitting Zaun batted .244 with four homers and 13 RBIs in 56 games. The 15-year veteran has also played for Colorado, Florida, Houston, Kansas City, Texas and Toronto, after beginning his career with the Orioles in 1995.
Tampa Bay manager Joe Maddon said he values Zaun's handling of pitchers, his clubhouse presence and his experience in the AL East, as the Rays attempt to chase down a playoff berth. They entered Friday 2½ games out of the wild-card lead and six games behind the New York Yankees in the AL East.
"He's going to have a positive impact on us getting back to the World Series," Maddon said from Seattle before Friday night's game.
Zaun was due to meet his new team late Friday. The Rays designated backup catcher Michel Hernandez for assignment to clear roster space for Zaun after their 7-6 loss in 11 innings at Seattle.
Maddon called Hernandez "a class act" who he hopes clears waivers and stays with the organization.
Wieters, the Orioles' first-round pick in 2007, is hitting .268 with three homers and 14 RBIs in 46 games since being called up May 29.
Moeller hit .200 with one homer and two RBIs in 15 games with the Orioles earlier this season.