ARLINGTON, Texas (AP) — Texas Rangers manager Ron Washington unexpectedly resigned Friday, saying he needed to devote his full attention to an "off-the-field personal matter."

The stunning announcement came a day after the Rangers (53-87) lost their sixth straight game and became the first team in the majors mathematically eliminated from playoff contention. Only three years ago, Texas reached its second consecutive World Series under Washington.

"I have submitted my resignation from the job I love — managing the Rangers — in order to devote my full attention to addressing an off-the-field personal matter. As painful as it is, stepping away from the game is what's best for me and my family," Washington said. "This is in no way related to the disappointing performance of the team this season. We were already discussing 2015 and looking forward to getting the Rangers back to postseason contention."

Washington, in his eighth season and expected back in 2015, said it had been a privilege to be part of some of the best seasons in Rangers history and that he was grateful for the opportunity.

"I deeply regret that I've let down the Rangers organization and our great fans," Washington said, who ended his statement asking for privacy.

General manager Jon Daniels also refused to go into specifics for the reasons for Washington's decision, outside of saying that the manager had given the team permission to acknowledge that the move "was not drug-related."

During spring training in 2010, it was disclosed that Washington had admitted to using cocaine once the previous year, but team executives stood by him. The manager got a two-year contract extension in 2012, then during spring training earlier this year had another season added through 2015.

When asked if people should be concerned for Washington or someone in his family, Daniels again would not get into specifics. The 62-year-old Washington is married, but has no children.

"I certainly think well-wishes and thoughts for him and his family are appropriate," Daniels said.

Players were shocked.

"It's like losing your dad," pitcher Derek Holland said. "I was extremely close with him. He's taught me a lot both on and off the field and I didn't see any of this coming at all. I'm lost for words."

The Rangers have been plagued by injuries this season. Slugger Prince Fielder and leadoff hitter Shin-Soo Choo, the primary additions last winter, are among an MLB-high 14 players on the disabled list. Also injured are ace pitcher Yu Darvish and left-handers Matt Harrison and Martin Perez.

In a 10-2 loss to Seattle on Thursday night, two more pitchers made their big league debuts for Texas. The Rangers have already set major league records using 63 overall players and 40 pitchers this season.

"This has been a difficult season for the team on the field for a variety of reasons, but it was very clear throughout the organization, publicly, privately, and with Ron, that he was coming back," Daniels said. "We were planning on him to be back as our manager for 2015, and the bottom line is that you don't have a season like we had without a number of things going wrong. ... While we're disappointed, we accept Ron's decision."

Washington, hired after the 2006 season to replace the fired Buck Showalter, won a team record 664 of his 1275 games and was manager in the Rangers' only World Series seasons.