But somewhere between the Legends Field clubhouse -- where Hughes appears to spend most of his time attending to a growing pile of autograph requests -- and the mound, something else begins to set in.
When Hughes throws, as he did on Saturday to the veteran Yankees catcher, crowds assemble and intangibles appear. For some, it might as well be a flashing neon sign, reading, "The kid belongs."
"That maturity, it just stands out," Posada said. "The attitude, you see it. It's not about being cocky. It's just the way he walks around, he belongs here. He acts like a big leaguer."
Hughes is among the Yankees' non-roster invitees to Major League camp this spring, but that seems to be just a formality. Conceivably, Hughes might end up experiencing the most big-league service time of any player on the list.
"Everyone knows Philip is an extraordinary athlete," pitching coach Ron Guidry said. "The kid has a lot of composure. He wants to make this club. So does everybody else, [but] I just think he might be a step above a lot of guys."
The Yankees' No. 1 selection in the 2004 First-Year Player Draft from Foothill High School in Santa Ana, Calif., Hughes has experienced a meteoric rise through the system. Through 237 1/3 Minor League innings, Hughes has compiled a 21-7 record and a 2.13 ERA.
He wrapped up the 2006 season with Double-A Trenton of the Eastern League, and believes his progression has delivered him to the proper place.
"I'd say I'm right on schedule," Hughes said. "This is where I thought I would be. I can say I've come a long way since I was pitching in high school, just by having an idea of how to get hitters out.
"If I would have had to guess what position I'd be back in 2004 [on draft day], I'd probably say right about where I'm at. I don't feel like I'm ahead of pace or behind at all."
With their five-man starting rotation already penciled in -- and both Carl Pavano and Kei Igawa appearing formidable early in camp -- Hughes' only clear shot at making the Yankees' Opening Day roster might arise via injury.
General manager Brian Cashman has called a scenario where Hughes would appear in April "unlikely," and manager Joe Torre said that the Yankees would prefer to see Hughes test himself against Triple-A hitters before taking up residence at Yankee Stadium.
That's not to say Hughes couldn't handle the jump. Posada said Hughes' demeanor reminded him of catching a young Andy Pettitte in 1993, when the two were playing together with Prince William of the Class A Carolina League.
Even then, Posada said he could tell Pettitte was destined for the big leagues. Acknowledging the lack of space on the Yanks' 2007 25-man roster, Posada said he nevertheless sees big-league qualities in Hughes.
"I'm pretty sure he could come north Opening Day," Posada said. "You'd hate to have a guy like that not throwing, so you've got to have him in Triple-A and you've got to have him throwing."
Scouts have deemed Hughes' repertoire to be Major League-ready at the present time. Hughes has said that his primary objective in Spring Training is to further develop his changeup to complement his mid-90s fastball and sharp-breaking curveball.
Hughes is also tinkering with a slider after being ordered to temporarily scrap the pitch in favor of re-learning his curveball, which he had last thrown in high school.
He insists that he is content with projections that have him beginning the season with Scranton/Wilkes-Barre of the International League, where the Yankees' new Triple-A farm club is poised to boast a powerhouse pitching rotation.
In addition to Hughes, a number of other participants in the Yankees' Spring Training camp -- hurlers Tyler Clippard, Ross Ohlendorf and Humberto Sanchez among them -- are opening eyes, leading Guidry to wonder if the 2007 youth movement is the best the Yankees have assembled in recent memory.
"You always say, 'Man, you've got some great arms,'" Guidry said. "I said the same thing last year, but it's moreso this year."
Arguably the brightest of those blossoming hurlers, Hughes remains confident he will be able to handle New York whenever the chance arrives.
"I believe I'm ready," Hughes said. "If I was given an opportunity, I'd surely go out and do what I'm capable of doing. To me, I think I am [ready], but they pay a lot of other guys a lot of money to make those decisions."
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.