Griffin, 34, says he can't shoot a basketball or throw a ball because his right shoulder is completely shot. He also now brushes his teeth with his left hand even though he was born right-handed.
"I physically can't (come back). I didn't want to be done, in the beginning," Griffin said on Ariel Helwani's radio show. "When I announced my retirement, that was actually when I was trying to come back and I realized, it just wasn't viable. It passed me by. My shoulder is done.
"I brush my teeth with my left hand now. That's just the way it goes. I can't shoot a basketball, I can't throw any kind of ball. I was right handed. The last three years, I was kinda fighting with one arm, on and off. My training camp was, I don't want to call it Frank Mir style, but it was Frank Mir style. It's like, I'm going to work on whatever hurts the least today. What are we doing today? Well, what's not broken today? That's what we're going to do today."
Griffin also advised current UFC athletes to have a post-fighting career plan to make sure they have opportunities to continue to make money after they are done brawling inside the cage.
"I think if you've fought more than three fights in the UFC and you're not financially ahead, you're either doing something wrong or you just need to quit. Your first two fights, your first two camps, yeah, you're going to maybe even go into debt on those," Griffin said. "But if you've had two or three wins and you're still not finding ways to get financially ahead, you might just do something else.
"Realistically, if you're doing it right, you should have time during a camp or during life to engage and learn another skill set. An occupational therapist, a physical therapist, an MRI tech. It'll never be as great as fighting, realistically. I wouldn't tell somebody who's 22, 'Hey, it's just as good of a job. Checking people into the hospital [instead of] fighting, it's going to feel the exact same.' Nothing is going to feel like fighting again. But it's going to feel better than looking around and wondering, 'Okay, what do I do now?'"
Griffin hasn't fought in over a year. The last time he entered the cage, he defeated Tito Ortiz via unanimous decision at UFC 148.
In May of this year, it was announced at the post-event news conference for UFC 160 that Griffin had retired from MMA fighting, citing chronic injuries.