There’s a lot of excitement about the San Francisco 49ers’ new coach Chip Kelly, as there should be.

There was a lot of excitement in Philadelphia three years ago when the Eagles hired him. But after two 10-6 seasons, that situation took a turn for the worse, leading to his dismissal.

So what does Chip need to do differently in order to make the 49ers competitive in the NFL’s toughest division? Based on years of covering Chip in Philadelphia and Oregon, I can’t agree with the conventional wisdom.

Others have argued that the fundamental problem was Chip’s personality, his uneven personnel moves, or Kelly’s battles with GM Howie Roseman. (Sound familiar, Niners fans?) All of these hurt, but if the Eagles had kept winning, he would still be in Philly.

When Kelly first came to the NFL three years ago, several writers predicted that Chip’s “college boy” approach would not work in the NFL. That is partially true, but not for the reasons anyone expected.

The problem was that Chip stubbornly stuck to his system, which is based on six interlocking elements: Tempo, Scheme, Versatility, Deception, Science and Culture. When the system works, these elements reinforce each other to produce astonishing power.

But when the system malfunctions, the interlocking elements drag each other down in the same way. It’s an all-or-nothing approach that wins or loses in streaks, and for reasons I’ll explore in a second, big chunks of it will never work as well in the NFL as they did in college.

Chip Kelly may well become a successful NFL coach again, but only if he rethinks the system he developed in Oregon from the ground up. That will be difficult to do while he is taking control of a franchise that needed a lot of rebuilding before he was even hired.

The Conventional Wisdom

The standard narrative now is that Chip is “emotionally stunted” in some way that no one apparently noticed in his first 25 years of coaching, that Chip Kelly the GM ruined things for Chip Kelly the coach, and that bureacratic infighting with GM Howie Roseman undermined his position. I don’t think that’s what happened.

Lack of Emotional Intelligence

Kelly is gruff and not all “Kumbaya and hug you the first time I meet you” by his own description, but that’s true of a lot of coaches (and bosses generally). His straight-faced, ball-busting sense of humor takes some getting used to, and his glare is frankly intimidating (especially after a loss). But he’s also jokey, self-deprecating, and focused on winning. Even after he was fired — when it actually helped a player’s position with the team to criticize Kelly — very few did, and several stuck up for him publicly.

Personnel Moves

Some of Kelly’s personnel moves were disasters (signing DeMarco Murray after Frank Gore reneged on a tentative deal), while others were very slow to pay dividends. Byron Maxwell and Sam Bradford were just bad early in the season but playing well by the end. Draft pick Nelson Agholor was a bust, and ILB Kiko Alonso was ineffective after reinjuring his wounded knee in week two.

But others were big successes, especially on defense. Chip converted forgotten CB Walter Thurmond into an excellent safety. Rookie ILB Jordan Hicks (3rd round) was a defensive rookie of the year candidate and major playmaker until he tore his pectoral muscle, and by year’s end CB Eric Rowe was holding his own against the likes of Odell Beckham Jr., Sammy Watkins and John Brown.

Hopefully, Chip learned that chemistry is elusive and slow to rebuild in the NFL, which is one reason few teams churn the roster as fast as he did last year.

Bureaucratic Battles

Chip was not the first Eagles coach or staffer to tangle with team executive Howie Roseman, a close friend of owner Jeffrey Lurie and a world-class bureaucratic infighter. But he wrestled Roseman more successfully than most.

On December 31, 2014, Roseman fired Tom Gamble, the 49ers assistant GM who was then the Eagles VP of Personnel (and Chip Kelly’s closest front office ally).

This was widely seen as Roseman asserting control over the coach — until two days later, when owner Lurie announced that Roseman had been kicked upstairs (with a raise) while Chip took complete control over personnel.

Suddenly, harsh portraits of the seemingly vanquished Roseman emerged in the press. Reporter Geoff Mosher of CSN Philly wrote of the GM that, “Roseman was also distrustful of his staff, fearing that underlings would try to climb the ladder and snatch away his job the same way he did as he worked his way up the chain for 16 years.

“His paranoia either drove other talented executives away or landed them pink slips. That’s why guys like Jason Licht, Marc Ross, Tom Heckert, Louis Riddick, Tom Gamble and others had short careers with the Eagles as Roseman worked his way up.”

But Roseman was playing the long game. Before the last game of the 2015 season, owner Lurie announced Chip’s firing in an email to season ticket holders, even before players were told. He said that Howie Roseman would join him and the team president on the search committee for a new coach.

Oh, and reporter Mosher, who sketched such a dark portrait of the former GM? CSN — dependent on the team for access to players and information — quietly declined to renew his contract a few months later, at the end of training camp.

There’s no doubt that Howie Roseman played a key role in Chip’s firing. And the Eagles have had trouble filling their head coach position, with several candidates (Adam Gase, Tom Coughlin, and Ben McAdoo) reportedly turning them down. Concern over tangling with Roseman may have been a factor.

But it would be a mistake to pin Chip’s firing solely on his front office nemesis. The Eagles did not do well in 2015 and the trend arrow was pointing in the wrong direction. If the team had won 10 games and the division title, Kelly would still be coach.

To understand what went wrong (and right) in Philadelphia, it helps to look at how Chip Kelly’s program works.

Chip’s System

There are a lot of simplistic takes on Chip Kelly’s system, with people writing that he needs a mobile quarterback, passes all of the time, uses lots of trick plays, and always goes for 2-point conversions.

None of that is true. His offense has always been run-focused, and of his last three starting quarterbacks, Nick Foles — who had a slower 40-yard dash time than four of his five offensive lineman — ran the most. Which was still not very much.

Kelly’s system is unique and relies on six interlocking elements: Tempo, Scheme, Versatility, Deception, Science and Culture.

The elements can’t be understood separately, because the tempo only works when the other elements support it.

Take the common criticism that the hurry-up, no huddle offense puts more pressure on his team’s defenders because they face more snaps. That would be true in a vacuum, but not when the system is working, because the other elements offset that problem.

The gambling, takeaway-focused defensive Scheme should either turn the ball over, or give up quicker scores en route to a shootout. Versatility and Deception help you rotate deeper into your bench and spread out the workload. Sports Science reduces soft-tissue injuries and keeps players fresher. Culture should help the team weather setbacks and support each other.

Here’s a quick summary of how the elements combine.

Tempo — It applies to every part of the team, in practice even more than games. The Eagles practices were shorter than most teams’ but had many more repetitions of plays (or “reps”), all videotaped for later analysis. Two ex-players — LeSean McCoy and Cary Williams — have complained about the grueling pace.

(Kelly lightened up a bit after Williams’ comments.)

Chip wants plays to be muscle memory by game time, for better execution. In 2009, he told assembled coaches at a Nike clinic that “If your players have not run that play in a critical situation over a thousand times in practice, you will not have a chance to be successful.”

And when he says a thousand times, he means that literally.