PHILADELPHIA (CBS) — The Philadelphia Phillies will not extend the contract of Senior Vice President & General Manager Ruben Amaro Jr., the team announced on Thursday afternoon.

The team has named Assistant General Manager Scott Proefrock as Interim General Manager, effective immediately.

Amaro, 50, took over as Phillies general manager in November of 2008, after serving as assistant GM for 10 years.

“It’s never an easy decision to make a change,” said Andy MacPhail, Phillies incoming president. “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.”

“The Phillies ownership fully supports Andy’s decision not to extend Ruben Amaro’s contract,” said Partner John Middleton.  “As a group, we have tremendous respect for Ruben, who has been a significant contributor to this organization. This decision is about taking the club in a new direction and that will be facilitated by new leadership.”

The Phillies announced they will immediately begin to search for Amaro’s permanent replacement. The Phillies will hold a press conference regarding Amaro’s departure from the club Thursday at 3:00 p.m.