The medication is Zoloft, a commonly prescribed anti-depressant that Greinke credits for enabling him to manage social anxiety disorder and depression. With the medication, Greinke returned to baseball after walking away in 2006, won the 2009 American League Cy Young Award and signed a record-breaking $147 million deal to pitch for the Dodgers.
"The medicine is the greatest thing ever," said Greinke, addressing the issue publicly for only the second time since his diagnosis. "The only problem is that I feel it makes me a little tired, that's the only complaint. It's amazing. I wish I had known about it before. I didn't know there was anything for that. I don't know why I didn't figure it out. I guess I didn't realize there was anything wrong with me. But there was."
Excelling at the highest levels of the sport is tough enough, but Greinke has done it after learning how to survive within himself. Before controlling his disorder with the medication, Greinke said he thought about self-medication of the abusive type. That was in 2006, in his third season as a Major Leaguer, when he struggled with the Kansas City Royals as a 22-year-old former first-round Draft pick.
"At the time, I didn't drink or smoke, and thought that the only way to get through it was to get involved in that stuff, but that would just temporarily help," he said. "I decided that wasn't best, it just wasn't me. That would be hiding from the real problem, so I decided to leave baseball."
Despite the dichotomy of selecting a career in which the scrutiny is obsessive, Greinke said it always made sense to him because of his passion for baseball competition. He said he was raised to do what he wanted to do, and he wanted to play baseball.
He just didn't want the growing anxiety he felt going to the park every day, although he said he realized the anxiety started "a little before high school. I guess I always had it a little bit, and it got worse in high school."
It kept getting worse until he couldn't take it anymore, or at least couldn't take the combination of his anxiety and his chosen profession.
"I didn't have a family at the time, so there was no reason to go through the pain," he said. "If I would have had two kids, I would have kept dealing with it. There was no reason to push through it. Why put myself through the torture when I didn't enjoy it?"
Greinke said he can count on one hand the number of people with similar health conditions who have reached out to him for speaking out. He acknowledges that some athletes fear the stigma of admitting that they aren't bulletproof, but he's not wired that way.
"I'm not ashamed of anything," he said. "If I do something wrong -- like last year I broke a rib playing basketball in Spring Training -- if I make a mistake I want to pay the consequences I deserve. I'm not a good liar. I just tell the truth, I think that's the best way."
With the medication, things have turned out pretty well for the 29-year-old. He married a former Dallas Cowboys cheerleader. He's been an All-Star, and now he's wealthier than he could have ever imagined. He's known as a fierce competitor.
"I play to see what I can accomplish," he said. "I don't play for fun. I play to see how good I can be."
He also wants his team to excel. He researched the teams that pursued him during free agency, studying their rosters and farm systems to assure he wouldn't wind up in a rebuilding phase. With the deep pockets and championship aspirations of the new Dodgers owners, Los Angeles became a logical landing spot.
He said he's still uncomfortable if recognized on the street, which he hopes won't be a problem in a city as big as Los Angeles, although the traffic is intimidating enough that he "looked into" the viability of commuting from the beach to Dodger Stadium by helicopter, only to find that that's not an option.
Some former teammates have characterized Greinke as a loner, particularly because he doesn't enjoy idle chatter. But manager Don Mattingly said those portrayals seem overblown from what he's seen.
"After meeting him over the winter, I feel like this is a non-issue," he said. "He's up-front with how he deals with it. He doesn't stay to himself as much as you think. He's a baseball junkie -- it's pretty amazing really. I think he'll fit in fine with the guys. It takes all types. Some are funny, some are loud, some are quiet. It takes all types to make a club."