The Braves designated Stewart for assignment Sunday, Kevin McAlpin of 680 The Fan Atlanta reports.
Stewart's removal from the active and 40-man rosters clears a spot with the big club for corner infielder Rio Ruiz, who was promoted from Triple-A Gwinnett in a corresponding move. The 35-year-old backstop had been serving as the Braves' backup catcher the last few days, but he fell to No. 3 on the depth chart after Kurt Suzuki (triceps) returned to the lineup Saturday against the Marlins.