"I'm glad to be back," Jeffress said. "When I walked into that clubhouse, it was a great feeling."
Jeffress said he wanted to apologize to teammates, fans and Major League Baseball for what happened.
"I made a big mistake," Jeffress said. "I regret it daily, from the bottom of my heart. I'm moving forward. I'm still sick and I'm still working on that. But I am a better and wiser person."
Jeffress addressed his teammates in a closed-door meeting before batting practice.
"I think it was good," Rangers manager Jeff Banister said. "The ability for Jeremy to stand up in front his peers, explain to them where he is at … the remorse, the accountability and the vulnerability, it was healthy for him and our players. It was important for them to see he is OK and is on the right path, moving in the right direction."
Jeffress also suffers from juvenile epilepsy. In addition to his alcohol use, the time in the clinic also helped deal with the issues that come from that, including anxiety and seizures.
"The doctors, psychiatrist, therapists, they formed a team and got to the bottom of the situation and what was going on," Jeffress said. "What my brain was thinking about and what made those decisions come up. The biggest thing was I was making decisions based on myself and what made me happy. I was not thinking how it affected loved ones, teammates, business people, family. It helped me a great deal to see how it affected them.
"I've been down before. My road has been rocky. Everybody is not perfect, but it is how you come back and see what you become. I'm very confident. I have been through the fire before. I'm back."
Jeffress stayed active in the clinic working out, running and some light lifting of weight. He also threw every day but it was basically throwing a baseball against a wall.
"I was putting holes in the wall," Jeffress said.
Jeffress is expected to be actived on Friday but may need a couple of sessions off a mound before he pitches in a game. A simulated game is also a possibility. He hasn't pitched in a game since Aug. 23.
"It will be a process to get him back on the field," general manager Jon Daniels said. "It's step by step, day by day. Get him accustomed to the day to day grind and a throwing program."
Jeffress is still a candidate to be on the postseason roster.
"I want to be on the playoff roster," Jeffress said. "It could be a once in a lifetime experience. But I know I've got myself in a better state of mind so I'll be OK with it if I'm not."