PHILADELPHIA – The Philadelphia Phillies fired General Manager Ruben Amaro Jr. on Thursday, completing a cycle of turnover for a team going through its worst season in 43 years.

Manager Ryne Sandberg resigned in June, and Andy MacPhail was hired to replace outgoing president Pat Gillick after the season.

“We needed a fresh perspective, a fresh approach,” MacPhail said.

Assistant general manager Scott Proefrock replaces Amaro as interim general manager. MacPhail hopes to hire a new GM before the end of October. He hasn’t made a decision on interim manager Pete Mackanin.

“It’s never an easy decision to make a change,” MacPhail said. “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 have the worst record in the majors at 54-86 and will miss the postseason for the fourth straight year after winning five consecutive NL East titles. They’re on pace to lose 100 games for the first time since going 47-107 in 1961 and their .386 winning percentage is the lowest since 1972.

MacPhail said he didn’t make a final decision on Amaro’s status until three or four days ago. He made the move with 22 games remaining to give Amaro, who was in the final year of his contract, an opportunity to pursue one of the four openings for GM jobs.

“This was more difficult than I anticipated,” he said.

Amaro replaced Gillick, who retired after the Phillies won the 2008 World Series and became a senior adviser. Gillick then replaced David Montgomery as team president on an interim basis last year and chose MacPhail to be his successor in June. Amaro previously served 10 years as assistant GM.

Amaro rose from team batboy in 1980-83 to playing for the Phillies for five seasons in the 1990s. He guided the Phillies to the 2009 NL pennant, three division titles and most wins in franchise history (102) in 2011.

RANGERS: Designated hitter Josh Hamilton will have an arthroscopic procedure on his left knee Friday, and the Rangers hope he’ll return before the end of the season.

Hamilton was hitting .257 in 40 games with six homers and 21 RBI.

Hamilton was on the 15-day disabled list last month with left knee inflammation and had two pinch-hit at-bats since Sept. 1.

He began the season on the DL after right shoulder surgery and was bothered by a left hamstring strain in June.

METS: Pitching coach Dan Warthen was taken to an Atlanta hospital after experiencing an irregular heartbeat prior to Thursday night’s game against the Braves.