The Phillies will introduce Ruben Amaro Jr. as their new general manager this morning during a news conference at Citizens Bank Park.

Amaro, 43, has been assistant general manager of the Phillies since 1998 and had worked for the past three seasons under Pat Gillick, the man whom he is succeeding as general manager.

The club said the search to determine Gillick's replacement came down to Amaro and Mike Arbuckle, the team's assistant general manager of scouting and player development. Now that Amaro has the job, Arbuckle, 58, who has been a member of the Phillies' front office since 1992, is expected to leave the organization.

Amaro seemingly was groomed for the GM's job since he joined the front office. Son of Ruben Amaro Sr., a former shortstop and coach for the Phillies, the younger Amaro was involved in contract negotiations with players on the 40-man roster, as well as with free agents.

He also served as the Phillies' official out front, making announcements such as the contract extension given earlier this season to pitcher Brad Lidge, when Gillick chose to stay in the background.

Amaro, a graduate of Penn Charter and Stanford, spent five of his final seven major-league seasons with the Phillies. He played for the 1993 National League champion Phillies, as well as the 1995 Cleveland Indians, the American League champion.

Gillick served three years in the general manager's job. His contract expired Friday.

Team president David Montgomery and Gillick are to be at today's news conference with Amaro, who will leave immediately afterward to attend the general managers' meeting in Dana Point, Calif.