The Phillies have dismissed GM Ruben Amaro Jr., effective immediately, president-in-waiting Andy MacPhail announced Thursday.

"It's never an easy decision to make a change," MacPhail said in a statement. "Ruben has had a direct impact on some of the best years in the team's history. He helped to create some great memories for Phillies fans with his accomplishments, but in order to return to a top-contending club, we believe this is the right thing to do as we continue the rebuilding process."