Riley, Salling, Shum and Morris are leaving 'Glee' Actress Amber Riley attends the Fox All-Star Party in Los Angeles on July 23, 2012. LOS ANGELES, June 28 (UPI) -- Amber Riley, Mark Salling, Harry Shum Jr. and Heather Morris are leaving the Ohio high school-set musical dramedy series "Glee," TVLine reported. Although the quartet won't appear regularly on the show in Season 5, they could return as guests, the television news website said. Former star Dianna Agron, who only appeared in a handful of episodes last season, will not return next season except for a possible guest appearance, TVLine said. Season 5 is to premiere Sept. 19 on Fox.