Ryan, 66, said he is not set on staying away from baseball, but does not yet know in what capacity he will be involved.
"Will I be the CEO of another major league ballclub? No, I won't," Ryan said at a news conference at Rangers Ballpark.
"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."
There are no plans in place to name a new CEO, but Rangers executive vice president Rob Matwick will take on extra responsibilities in the meantime, including representing the team at MLB meetings. Ryan had been CEO since March 2011.
For Ryan, this means spending more time with his grandchildren and work on his ranch in Texas.
"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."
He also sold his ownership interest. With that sum, plus incentives, his exit package is expected to exceed $10 million.