He likes to think about a different day, the day he will return to the Majors.
"It's going to be the best day of my life, that's the best thing that I can say," Greenberg said. "Because of what I've gone through over the last few years, it's going to be a special day. I'm looking forward to it. I have worked so hard and dealt with so much stuff, it's just going to be the greatest moment ever."
Greenberg, granted a release by the Royals in Spring Training, is back with a Major League organization after manning center field for the Bridgeport Bluefish of the independent Atlantic League to start the season.
He is hitting .297 in 25 games since signing with the Arkansas Travelers, the Double-A affiliate of the Angels.
"There's no question, as a whole at this point in my career that I'm a better all-around player than even when I was called up three years ago," Greenberg said. "It's exciting."
Greenberg's stay with the Cubs lasted 45 one-hundredths of a second in 2005. That's how long it takes a 92-mph fastball to travel the 60 feet, 6 inches from the mound to home plate.
In this case, it was from Valerio De Los Santos' left hand to behind Greenberg's right ear. Greenberg was hit on the first pitch of his only Major League plate appearance and has yet to make it back with the Cubs, the Dodgers, the Royals or the Angels.
He was originally placed on the disabled list with a concussion, but the after-effects included blackouts and doctors' visits. Eventually, he was diagnosed with vertigo.
Greenberg estimated he has been plunked at least 10 times this year, once at the top of one of his shoulders. It doesn't faze him anymore, which allows more time to focus on him hitting the ball instead of the other way around.
"At this point, it doesn't weigh on me like it used to, because I'm more at peace as a player," Greenberg said. "I made a lot of adjustments and improvements over the last couple years. Last year was a stepping stone, getting back on track. I worked hard this offseason on mental and physical changes, concentrating more on hitting the ball on the ground and getting the base hits instead of hitting the ball out of the ballpark."
From Jacksonville, Fla., to Wichita, Kan., from ESPN to the New York Times, everybody everywhere asked Greenberg about that half-second and the ensuing years of a feel-good comeback story.
The comparisons to "Moonlight" Graham from "Field of Dreams" are getting old. So is Greenberg, once an Upper Deck-baseball-card-worthy prospect and now a 27-year-old Minor League journeyman.
"The older you get, the harder it becomes to stick as an everyday guy," Greenberg said. "At the end of the day, I made it up when I was 24 years old. I don't feel like I'm getting older, just mentally smarter, more intelligent and a better ball player. There are many guys starting their careers getting to the big leagues at 27, 28. I've got a lot of years left in me."
He and the Royals mutually parted ways because of what Greenberg called a "numbers game." His odds of moving past other highly drafted outfielders in the farm system were not worth a gamble.
Greenberg found a better opportunity to re-reach the Majors when the Angels called. He is under contract through the end of the season, and the team is already interested in re-signing him, director of player development Abe Flores said.
Don't get giddy. Greenberg's chances of getting back to the Majors soon, even a September callup, are bleak. "For us, it would be a long shot," Flores said. "But in the future, it could be a possibility. Every day that he is with us, he's interviewing for that possibility. And he's doing very well."
Greenberg doesn't like to play the "what if?" game.
Like, what if Felix Pie hadn't been hampered by an ankle injury when Cubs general manager Jim Hendry scanned the Minors for callups on July 8, 2005?
Or, what if right-handed Ronny Cedeno would have been called to pinch-hit instead against the Marlins' left-handed De Los Santos?
And, what if the lefty Greenberg leaned back, stepped out of the box or somehow avoided that first-pitch fastball?
"I certainly don't think about it," Greenberg said. "The only time it's brought up is when a new teammate, friend, reporter, somebody wants to talk about it. To be honest, I've become so numb to it."
Greenberg has a message for all the well-wishers, many of whom are Cubs fans.
"I'm going to get back, let them all know," he said. "It's going to be a great time."
Nick Zaccardi is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.