OAKLAND, Calif. - The Oakland Athletics fired manager Bob Geren yesterday in the midst of a nine-game losing streak that has sent them tumbling to the bottom of the American League West standings.

"It felt like at this point a change was necessary," general manager Billy Beane said. "It got to the point where the emphasis was on the status of the manager on a daily basis and no longer on the field. When that starts to happen, you need to shift the focus to what's really important, which is performance. That's how we came to this decision."

Former Arizona manager Bob Melvin will take over for the rest of the season as interim manager in the first midseason managerial change for the organization in a quarter century.

Geren's four-plus season tenure at the helm in Oakland was marked by numerous injuries, a lack of offense and high-profile departures as he was unable to post a winning season after taking over a division championship team from Ken Macha. Geren, in the final year of his contract, posted a 334-376 record with the A's, including a 27-36 mark this season.

The A's currently have four starting pitchers on the disabled list, including a season-ending shoulder injury for Dallas Braden. Oakland also was without injured All-Star closer Andrew Bailey for the first 2 months and was last in the American League with just 223 runs through the 63 games under Geren this season.

"Bob Melvin will inherit some of the challenges that Bob had," Beane said. "Bob lost four starting pitchers in the space of 3 weeks. That was a tough body blow for the team. That was very difficult from Bob's standpoint. We also have to be realistic here starting out of the gate how we manage around those four guys on the disabled list."

The beleaguered manager had come under criticism from his bullpen in recent weeks for a lack of communication with reliever Brian Fuentes and former Oakland closer Huston Street publicly criticized him.

But it was the rash of injuries and the total lack of offense that led to the current losing streak that spelled the end of his tenure. The current skid is the longest for the A's since a 10-gamer in July 2008 and the fifth-longest single-season losing streak since the team moved to Oakland in 1968.

This is the first time the A's have fired a manager during the season since getting rid of Jackie Moore after 73 games in 1986. Jeff Newman took over for 10 games on an interim basis before Tony La Russa was brought in to start a run that included four division titles and the 1989 World Series championship.

Beane said he started the process of evaluating Geren's status a few weeks ago before making the ultimate decision.

"Whenever you replace your manager, it's a drastic move," Beane said. "I've never had to do it in my tenure as general manager. This is a new script for myself. I don't know if you ever know what the right time is."

Geren, a longtime friend of Beane, was hired to replace Macha after the 2006 season. The A's won the division that year and their first playoff series since 1990 before being swept in the AL championship series by Detroit.

Melvin, 49, posted a 493-508 record in seven seasons as manager with Seattle and Arizona. He led the Diamondbacks to the NL West title in 1997 and also won 93 games in his rookie season with the Mariners in 2003.