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 team when he was appointed as the bullpen coach on February 14, 2007. He succeeded Rick Dempsey, who joined Mid-Atlantic Sports Network as the primary studio analyst for Orioles game broadcasts. He also served as both the major league field coordinator and bullpen coach during Spring Training in 2007, later assuming the role of interim bench coach after Tom Trebelhorn departed to attend to a family issue.