SURPRISE, Ariz. -- There is no doubt or ambiguity about who is running the Rangers right now. Nolan Ryan is in complete control of all areas of the organization and Chuck Greenberg is out completely.

Ryan ascended to undisputed boss of the organization when Greenberg resigned Friday as the Rangers' chief executive officer. Greenberg, who put together the ownership group that bought the team from former owner Tom Hicks last summer, is also selling his interest in the team and will no longer be associated with the Rangers.

Ryan, who has been club president for three years, will now also carry the title of CEO and oversee both the baseball and business operations. He will report to the Board of Directors for Rangers Baseball Express, led by co-chairmen Ray Davis and Bob Simpson.

The announcement was made official in a press conference at Rangers Ballpark in Arlington on Friday. Ryan, Simpson and Davis were in attendance.

"I'd like to say both to Bob and Ray, thank you for giving me this opportunity and having the confidence in me to fill this role, and I'm looking forward to it," Ryan said. "We're going to stay the course that we have set, which I think is very important. Ray and Bob both said we have some new people that have come on in our organization that are very talented, that I think will help lead us in the direction that we have set.

"I am very excited about that. We feel like that, with the team not only that we've put together on the field but also the team we have in the front office, we have positioned ourselves for bigger and better things, and we're quite excited about it."

Greenberg's resignation was unexpected and came seven months after the sale of the franchise had been approved by Major League Baseball. The abrupt departure suggests there was significant conflict between Ryan and Greenberg in how the team was being operated.

"From Chuck's perspective and mine, we probably had a little difference of opinion in our style, but I don't really want to go into it," Ryan said. "Chuck definitely had a very high passion for baseball."

Under the original agreement, Ryan was supposed to be in overall charge of baseball operations while Greenberg would oversee the business side of the franchise. There were times when those lines became blurred.

"I don't really think there was an event that created the separation that we had," Ryan said. "It was a combination in philosophies. It's like a marriage, you never know. You think things are going to work, but we all know in business, [it's not] until you really get in there on a day-to-day basis do you really get a true feel for how it's going to work."

Greenberg did take an active role in negotiations with pitcher Cliff Lee when he became a free agent after the season. Lee ultimately signed with the Phillies. Ryan declined to say whether Greenberg's involvement in the Lee negotiations caused any friction. But the Rangers' final six-year, $138 million bid was beyond what Ryan expected the club to offer.

"I'm not going to get into that," Ryan said. "Chuck has a lot of passion for the game and a lot of energy. But I'm not going to speculate on Cliff Lee or anyone else, as far as baseball is concerned."

Davis suggested there was also conflict between Greenberg and the Board of Directors.

"I don't want to put this all on Nolan," Davis said. "This was, if there was any conflict here, it was Nolan and also the board. This was a joint effort. This wasn't just all Nolan."

Greenberg was not available for comment on Friday but did issue a statement through the club that also suggested there was conflict, not only with Ryan but with Simpson and Davis as well.

"I have great respect for the Texas Rangers franchise and am enormously proud of all we have accomplished together since August," Greenberg said in a statement released by the team. "Unfortunately, Nolan Ryan, the co-chairmen and I have somewhat different styles. While I am disappointed we did not work through our differences, I remain wholeheartedly committed to doing what's right for the franchise.

"Together we concluded it is best for all concerned for me to sell my interest back to Rangers Baseball Express and move on. I do so with a heavy heart, but with every confidence in the direction that the new management team is taking the Rangers and, with Nolan at the helm, I know this franchise will continue to thrive and reach even greater heights both on and off the field."

Greenberg is a Pittsburgh sports attorney who moved quickly in 2009 to form a group to buy the Rangers after Hicks announced he was willing to sell the team. Greenberg recruited Ryan, who was hired by Hicks as club president in 2008, and they formed an alliance. He also persuaded Davis and Simpson to come aboard, and they were the major financial investors in the group. With Ryan on board and the group comprised mostly of local investors, Greenberg had the strong backing of the Commissioner's Office.

Hicks agreed to sell to Greenberg and his partners on Dec. 15, 2009. But the sale was blocked by the lending institutions that hold the debt on the Hicks Sports Group. Instead of the sale being completed by Opening Day, the Rangers ended up in United States Bankruptcy Court.

The issue was finally decided in an auction held Aug. 4-5 in Fort Worth, Texas, and Greenberg's group won out over Mavericks owner Mark Cuban and Houston businessman Jim Crane. The final sale price was $590 million, and was approved unanimously by the 29 other teams on Aug. 12.

"During the efforts to purchase the ballclub and then bankruptcy, and then subsequently the auction, the focus was on that and that's where everybody's energy and efforts went," Ryan said. "Our group of owners was united in trying to get this done, and that was our focus. As we got into the business side of it, we had differences of opinions."

Ryan said he expects to be able to oversee both the baseball and business side of the franchise. General manager Jon Daniels will continue to report directly to Ryan on the baseball side. Rick George was brought in from the PGA Tour in October and hired as chief operating officer to handle the business. That is expected to continue.

"With the team of people we have in place, I'm not a micromanager," Ryan said. "I really believe in hiring good people and allowing them to do their jobs. So it will definitely be a joint effort, not only in the front office, but as it's been in the baseball department."

Greenberg was hailed as a savior after his group won the auction and the Rangers were able to emerge from the strict financial constraints imposed by the Commissioner's Office while the club went through bankruptcy. Just over two months after the sale was approved, the Rangers defeated the Yankees in the American League Championship Series and went to the World Series for the first time in club history.

The Rangers lost to the Giants in the Fall Classic, but the momentum created by the sale in court and the success on the field spilled over into the offseason. Ticket sales are up, attendance at FanFest set an all-time record, and the Rangers announced that a new video board would be installed on top of the Home Run Porch in right field.

Greenberg made numerous appearances in the Dallas-Fort Worth area, becoming almost a rock star in popularity with the excitement that was being generated for the franchise. Now he is completely out of the picture.

"Chuck has a lot of energy and he had a passion for the game," Ryan said. "But under the circumstances we are dealing with now, versus the circumstances we were dealing with during the bankruptcy and MLB's control and the things we have experienced, we have a staff in place that has every bit that energy level and passion for the game. At the time, there were a lot of things we couldn't do under the circumstances that we were dealing with."