Not every player receives a welcome like Duncan did, or has the same type of breakout week, but learning to handle the extra attention is a process that all up-and-coming players face when stepping off the shuttle to New York. It's a transition as big as the city itself, and one that takes some getting used to.
"The real thing you hear from every player that's different here from anywhere, really anywhere else, is the media," Duncan said. "Other places aren't like this."
In his two seasons moving up and down from Triple-A to the big leagues, Mets outfielder Lastings Milledge has seen his fair share of attention from the New York media, and he's come to embrace it.
Milledge's behavior since signing on with the Mets has been controversial at times, as some have considered his on-field celebrations to be too much. This season, Milledge has toned it down a bit, but the 22-year-old still feels that he delivers when it comes to giving the Big Apple a good show.
"We're entertainers out there," Milledge said. "Everybody sees what everybody does, so it's something you have to take into consideration when you play."
Yankees reliever Sean Henn might not feel the same way, as he said he'd rather fly under the radar, but the 26-year-old has been up and down several times this season and still knows what it's like to get noticed in the big city -- even if it's not for his own accomplishments.
With the same build and coloring as Duncan, Henn said fans have mistaken him for his blond teammate while walking out of Yankee Stadium, and the one time a fan correctly identified Henn on the subway, he didn't even ask for an autograph.
"They said, 'Hey, are you Sean Henn?' and I said, 'Yeah,'" Henn recalled with a laugh. "They said, 'Will you tell Phil Hughes good job last night?' They wanted no part of me."
No matter its degree, going to The Show means players need to be aware of the more detailed scrutiny they will likely face in New York. For highly-touted young righty Hughes, the Minors was the dress rehearsal, helping to prepare him for the day he'd don pinstripes.
"I've kind of had to deal with the expectations and everything ever since I was drafted, so I kind of learned on a smaller scale how to deal with media, the fans, all that stuff," Hughes said. "Now, it's on a little bit bigger scale, but I still don't let it bother me."
Hughes said he tries to focus on performing and not get distracted by the media or the fans, but it goes without saying that playing the game is harder in the big leagues, too. Not only does the move to the Majors mean increased attention, it means increased pressure to find one's place.
"It's kind of a give and take," Mets reliever Jon Adkins said. "You can't get caught up in trying too hard, but you also can't just be not caring, either. You just try to stay in the middle."
Within the pulsating big league atmosphere that is only amplified in the big city, finding the right mental balance takes a certain level of ease. In Duncan's case, the ability to stay relaxed under the pressures of the Majors is something that has resulted from years of growing up with a professional ballplayer as a dad.
Duncan said his father, Cardinals pitching coach Dave Duncan, encouraged him and his younger brother, Chris, a member of the St. Louis team, to experience the nature of the media in the clubhouse while growing up. Sitting in on Mark McGwire's home run chase in 1998 and a World Series title in 2006 gave Duncan a familiarity with an atmosphere he would one day face in person.
"I've been around all that stuff, and you can get comfortable with it," Duncan said. "It's fine with me now. And when I'm comfortable with that type of situation, I'm able to slow myself down and really focus on what it is I need to do. I need to go out and play hard every day."
Often filling in the last slot on the roster, players on the shuttle know that every outing could conceivably be their last, and playing hard every day becomes increasingly more important. Without a solid performance, a new Major Leaguer could easily go right back to being an understudy, waiting in the wings for his next hour in the spotlight.
"It's tough going up and down with any organization, but being in New York, it's definitely a bigger stage," Henn said. "There's definitely pressure. I think any time you go up, you want to do your best, but I think there's a little bit shorter of a leash in New York. Winning here is the expectation -- they're not going to play around with the young guys."
Performance is certainly a large factor in deciding Major League fate, but it isn't the only one. Injuries and the needs of the particular club can send someone down, even if he's been doing just fine.
If anyone understands what it's like to move because of events beyond his control, it's former Mets utility man David Newhan. Bags get more and more consolidated with each re-packing for the 33-year-old, who has spent plenty of time in career on the move. Newhan started off this season with the Mets and was optioned to Triple-A New Orleans and recalled several times.
"That's the hardest part," Newhan said. "A lot of times, it's not a bearing on if you can play at this level or if you belong here, it's a bearing on the game and the economics of the game are set up. You just have to deal with it and keep your head on straight, because moping about it and not performing down there isn't going to get you back here. This is where everyone wants to be."
Duncan, to be sure, is no exception. He's doesn't know how long he'll be in New York, though he hopes there isn't an end to his stay, but he's not worrying about it, either. For now, he's enjoying his rookie season, playing his best, and taking it all in.
"I like to have a good time with everything, to see the good things out of all of this," Duncan said. "When you're in this position, it really is just what you make of it."