Trembley was promoted to Baltimore's major league coaching staff when he was named the team's bullpen coach on February 14, 2007. He succeeded Rick Dempsey, who joined the Mid-Atlantic Sports Network as the primary studio analyst for Orioles game telecasts. He was the major league field coordinator as well as the bullpen coach during Spring Training in 2007, and later was the interim bench coach, replacing Tom Trebelhorn, who left the club to attend to a family matter.
Trembley was elevated to Baltimore's major league coaching staff when he became the bullpen coach on February 14, 2007. He replaced Rick Dempsey, who moved to Mid-Atlantic Sports Network as the primary analyst for Orioles game broadcasts. Additionally, Trembley held dual roles as both field coordinator and bullpen coach during Spring Training in 2007, before assuming the interim bench coach position after Tom Trebelhorn left due to a family matter.