To know what constitutes a "Chip Kelly player" is to know why Chip Kelly doesn't want to be known.
After more than two years as the Eagles coach, few - if any - have been able to penetrate a wall built around family, friends, and colleagues who have been protective of Kelly's privacy.
Many have tried, to no avail, although a Washington Post story last week revealed that Kelly, thought to be a bachelor, was in fact once married for seven years.
"I don't think my friends or family should be bothered or have to answer questions about me," Kelly said last month during an hourlong interview.
His elusiveness has made Kelly only more Garboesque. Some, like maybe LeSean McCoy, might say it's all by design. Kelly said he isn't any different from others who seek to keep their private life private.
"I think most people do, don't they? Unless you're a Kardashian," he said.
And yet, most people aren't arguably the most intriguing Philadelphia sports figure of this century. Kelly, who has vast interests outside of football, was asked if he ever wanted to know more about the people he admires.
"I don't look at it from that point of view," he said. "I look at it from the Navy SEALs point of view: 'I do not advertise the nature of my work, nor do I seek recognition for my actions.' "
When asked for his favorite book, Kelly cited The Autobiography of Benjamin Franklin, an occasionally boastful narrative written by perhaps the most famous individual ever associated with Philadelphia.
But while Kelly's insistence on remaining in the shadows offers little insight into what makes him tick, it does say something about his preference for players, especially when you consider the Eagles' offseason.
Given full authority over football operations in January, Kelly made sweeping changes. The Eagles had already been acquiring players to fit Kelly's schemes and size/speed parameters, but there wasn't any ambiguity this offseason about who made the decisions.
Even though the Eagles had won 10 games in each of his first two seasons and were 9-3 before a three-game December slide knocked them out of the playoffs last year, Kelly said the team wasnt on the cusp of contending for a championship.
"I didn't feel we were close at the end of the year," he said.
The quest to move closer to an elusive Super Bowl begins in earnest next Sunday, when training camp opens at the NovaCare Complex. But can a team that underwent so much turnover - there could be as many as a dozen new starters - take the next step without regressing?
Kelly said many of the controversial moves - dealing McCoy and releasing guard Evan Mathis were two of the most scrutinized - were done primarily to clear salary cap space. But there has been enough evidence that players - starting with DeSean Jackson a year ago - were also discarded for failing to conform to Kelly's way.
McCoy said Kelly didn't respect star players and during an interview with ESPN charged him with getting rid of "all the good black players." Mathis, though, hasn't said anything quite as inflammatory and seemed to check off the chief requirements to being a "Chip Kelly player."
"Someone who works hard and is passionate about playing the game," Kelly said when asked for a definition.
The boldness of Kelly's decisions has generated split opinions. "Chipbots" - as some call his followers - have defended every move, while naysayers have forecasted doom and a quick return to college coaching.
Of those close to Kelly who are required to talk, such as defensive line assistant Jerry Azzinaro, his talents as a coach will translate to being a successful evaluator and general manager.
"I think it's an overall competency when it comes to football," Azzinaro said of Kelly. "Being able to view the big picture."
Kelly wants players who are concerned only with what they can control and aren't distracted by outside influences. It is the way he works. It has resulted in a climb to the heights of his profession. It is why he has no desire to let outsiders in or to use the media to craft a message or image.
"If you're thinking about crafting," Kelly said, "you're not spending enough time on your job."
Kelly likes to say that the only difference in his job since owner Jeffrey Lurie placed him in charge of personnel is that he now has final say. Even if that were true, it is a very significant difference.
He no longer has to answer to anyone, especially former general manager Howie Roseman, whom Lurie unceremoniously demoted in favor of Kelly. The coach already had authority over the in-season 53-man roster, but he had to confer with Roseman during the free agency and draft process.
Their relationship was contentious and Kelly had become convinced that Roseman wasn't the ideal man to pick the players for his schemes. He has publicly pinned last year's draft, and the Marcus Smith first-round selection, on Roseman.
Kelly has said he didn't engineer Roseman's ouster. "I disagree with the word takeover," he said when a question was phrased as such.
Roseman technically remains in charge of the cap and contracts, but team and league sources have said that his role has been marginalized. He has other responsibilities, but even Kelly isn't sure what they are.
"I think he does a good job in what his job is now in terms of overseeing contracts, in terms of overseeing all those other things that are under it," Kelly said. "There are some things he's doing - I don't know exactly what those are. Those are under the direction of Mr. Lurie."
Roseman has declined repeated interview requests since the front office shake-up. His office was moved from the football end of the building in February. Kelly said he didn't know whether Roseman was resentful.
"That's a question for him," Kelly said. "I never talked to him about it."
Kelly said he hasn't had to budget his time any differently since taking on more responsibility. His coaches have said that football operations have remained status quo.
"I don't do what a GM does," Kelly said. Indeed, Ed Marynowitz, who was promoted to vice president of player personnel, handles most of Roseman's old chores.
But Kelly made changes, inviting more voices to the evaluation table. He put a system in place in which the coaching staff had more input than previously.
"The position coaches - they've been around their style of players and they understand what they're looking for in a player," Azzinaro said. "And then they communicate that with [Kelly] and together you kind of figure out, 'What do you want this picture to look like?'"
The plan, Kelly said, was to shift resources from offense to defense. So McCoy, who was slated to earn around $12 million this season, was traded to the Bills for linebacker Kiko Alonso. And three-fourths of the secondary was revamped with the Eagles signing cornerback Byron Maxwell to a $63 million contract.
But given the opportunity to upgrade on offense at the most important position, Kelly pulled the trigger on a deal that sent quarterback Nick Foles to the Rams for Sam Bradford and his $13 million contract. The trade raised eyebrows because the Eagles also included a second round pick for the oft-injured quarterback.
"If you're not going to pick 1 or 2, how do you go get a quarterback?" Kelly said. "Peyton Manning switched teams because of an injury. Drew Brees switched teams because of an injury. So we went down that path."
Bradford wasn't the only addition with an extensive injury past. Last season alone, five new faces missed three games or more - Alonso (16), Maxwell (3), running back Ryan Mathews (10), defensive back Walter Thurmond (15), and receiver Miles Austin (4). Running back DeMarco Murray didn't miss a game, but sat out 11 games in his first three seasons.
"I think everybody in the NFL is 100 percent injury-prone," Kelly said.
Murray was signed after Jeremy Maclin left for the Chiefs. Other than failing to retain the Pro Bowl receiver, Kelly said the Eagles came close to hitting on all their objectives.
"I don't think things would have been much different if Howie was still in control," Kelly said. "I think we were all on the same pages in terms of making moves and trying to make this team better."
Culture beats talent?
But would Roseman have parted with a Pro Bowl tailback who had said he was willing to renegotiate his contract? Would he have released a Pro Bowl guard who had said he was ready to report for minicamp?
It's possible, but those decisions have the markings of a coach, especially one who professed "Culture beats scheme" during a sideline conversation with a practice squad player that was caught by NFL Films.
"That was a conversation with Jordan Kovacs at the end of the Carolina game and then all of sudden everybody wants to make that a banner that flies over this building," Kelly said. "That was a [conversation] I had with a player that was telling me how he really enjoyed being here."
But it's an atmosphere that has been carefully constructed by Kelly and, in many ways, reflects the mile-a-minute coach. Everything is structured in the interest of maximizing time and technological and scientific advances - some that have been documented, many that have not.
The requirements can be difficult for some players to embrace. But that's where the culture part enters. It is why Kelly places so much emphasis on character and having players who develop into leaders and can integrate new pieces into the program.
"There's been a changeover, but it's almost been fresh having new guys here and kind of teaching them the ways," center Jason Kelce said. "I think now I'm in a much different position than I was two, three years ago, even just one year ago. Right now, I think we have a very solid locker room that is eager to learn and get better."
Kelly has a three-pronged approach to evaluating players. Size and speed measurables come first, followed by scheme-specific talents and, lastly, character and intelligence. While "culture over scheme" may have indeed been overstated, Kelly still focuses on the third part of the process when describing his preference for players.
"We want a bunch of guys that love playing football," Kelly said, "not what football gets them."
It's the way some colleagues have described how Kelly feels about coaching. As for his life away from football, many have said they know very little about the man. Asked to name whom he interacts with most at the NovaCare Complex, Kelly named two janitors.
"Troy and Montrell," Kelly said. "Montrell is late night, Troy is early day. Those are the two guys I probably spend the most time with."
He could be joking. Or not.
Kelly said he doesn't read many football books. He has spoken before about some of the self-help and business model books he has read and cribbed ideas from. His admiration for The Autobiography of Benjamin Franklin was a new one.
"Just a very interesting read and he's a very interesting person," Kelly said. "Accomplished a lot, done a lot. I'm just amazed at what he accomplished in his life. You kind of feel like you don't do anything after you figure out what he did."
Franklin's book, written late in life, recounts only his first 51 years. For the 51-year-old Kelly, there is still more that he would like to accomplish. It's unlikely he'll ever tell the full story.