ARLINGTON, Texas -- Hall of Famer Nolan Ryan announced his resignation, effective at the end of the month, as CEO of the Texas Rangers on Thursday. He also sold his ownership stake in the club to co-chairmen of the board Bob Simpson and Ray Davis.
Ryan, 66, left the door open for a return to the game but said he hasn't decided what he will do with his future.
"Will I be the CEO of another major league ballclub? No, I won't," Ryan said at a news conference at Rangers Ballpark in Arlington. "But I'm not going to sit here today and tell you that I don't know what a year from now might bring. This might be the final chapter of my baseball career. If there was something else I did, it certainly wouldn't be in the role I had with the Rangers."
One of Ryan's sons, Reid, is the president of the Houston Astros, but he said that for now he wants to spend time with his grandchildren and work on his Texas ranch.
"You don't just wake up one day and make a decision of this magnitude," Ryan said. "It was something I'd been thinking about off and on for a while now. I felt like it was probably time for me to move on. It just felt like what I needed to do."
The Rangers had announced in a statement earlier Thursday that Ryan was retiring.
There are no plans to name a new CEO, but Rob Matwick, the Rangers' executive vice president of ballpark and event operations, will have added responsibilities. Davis said he will represent the club at MLB meetings and that he and Simpson will rotate that job every two or three years.
"On behalf of Major League Baseball, I thank Nolan for his service to the Texas Rangers since 2008, a successful era that has been most memorable to the club's fans," MLB commissioner Bud Selig said in a statement. "During times of significant change for the franchise, Nolan has been a constant -- accessible, dedicated and an icon to his fellow Texans who love our game."
President George W. Bush, a frequent guest in the seats next to Ryan's at Rangers Ballpark since the start of the 2009 season, said his friend "brought a lot" to the Rangers during his tenure, praising him as a pitcher and a person.
"The Rangers will miss his presence -- and I will miss sitting next to my pal at the ballpark," Bush said in a statement sent by his office. "Laura and I wish Nolan and Ruth all the very best."
Ryan was hired as president by former Rangers owner Tom Hicks in February 2008 and was given the title of CEO in March 2011 by the current ownership, headed by Simpson and Davis. Both men attended the news conference Thursday.
Ryan contemplated stepping down in March after ownership restructured the front office and gave general manager Jon Daniels the added title of president of baseball operations. Rick George, now the athletic director at the University of Colorado, was named president of business operations. That left Ryan as the CEO, but uncertain of his role. It took several face-to-face meetings with ownership, but Ryan decided to stay for the 2013 season.
"I had committed to charities and things and made some commitments," Ryan said. "I felt like I wanted to see how things worked out. I can't say just because we changed titles on some people that it drove me to this decision because that's not what it is."
Ryan said his relationship with Daniels is "good" and that it "didn't come into play on this" decision.
"I've enjoyed my time working with and learning from Nolan," Daniels said in an email. "We've shared a lot of successes together, along with many others here. I specifically appreciate his passion for the game and the way he treats people in and out of the organization. We wish him the best in whatever he chooses to do next."
Daniels was at the news conference but said he wanted Thursday to be about Ryan and ownership, so he didn't talk to reporters.
When Ryan arrived in 2008, Daniels was already the GM and he had hired manager Ron Washington the previous season. Ryan oversaw a club that improved dramatically, going from fighting for third in the AL West to winning the division in 2010 and '11 and making the World Series both seasons.
Ryan said he was proud of those achievements as well as the fact that so many fans supported the team -- the Rangers drew 3 million fans in each of the past two seasons.
"I know how hard it is to be a world champion," Ryan said. "To be as close as we got [in 2011] and not get there, there's no guarantees you'll get there again. That's been a bitter pill."
Simpson said he spent much of the past few days trying to get Ryan to change his mind but was unsuccessful. He said he's disappointed Ryan is leaving, but understands and respects the decision.
"What we've had that you'll miss is the forging of two camps -- youth and experience -- with a product that speaks for itself," Simpson said. "That's what we worked hard to preserve as long as possible. We all wanted to go forever."
Ryan will also be missed by the pitchers in the organization. He stressed getting more out of the club's starters and not allowing pitch counts to dictate performance. And when players had questions, Ryan would answer them.
"He was a mentor and a friend," pitcher Derek Holland said. "He helped me on and off the field. I'm devastated to hear the news that he's retiring. I'm going to miss him."
Ryan's impact for the Rangers began as a player when the future Hall of Famer signed as a free agent on Dec. 7, 1988. The Ryan Express threw two of his seven no-hitters for the Rangers and also reached several career milestones in his five seasons with Texas.
He recorded his 300th victory on July 30, 1990, at Milwaukee. He became the only pitcher in baseball history to reach 5,000 strikeouts when he fanned fellow Hall of Famer Rickey Henderson on Aug. 22, 1989, at Arlington Stadium. (Ryan finished his career with 5,714.)
Ryan ended his career as a Ranger on Sept. 22, 1993, at the age of 46. He was elected to the National Baseball Hall of Fame in 1999, receiving 98.79 percent of the vote, and is the only player in Cooperstown wearing a Rangers cap on his Hall of Fame plaque.
His No. 34 jersey is the only one worn by a Rangers player to be retired, and there is a statue of the pitcher at Rangers Ballpark.
Information from ESPNDallas.com's Todd Wills and The Associated Press is included in this report.