“You get to show us every single day what you can do, where you belong in this thing,” said Eagles Coach Chip Kelly. (Matt Smith/Associated Press)

It’s a new day at the Philadelphia Eagles’ practice facility, and the sun is blazing, music blaring, bedlam building. The ringmaster wears a sun visor, and every bit of the organized chaos that swirls around Chip Kelly makes perfect sense to the first-year head coach. No detail is too small, no problem too big.

There’s a reason behind everything here — from the wide-ranging music selection played during practices to the made-to-order smoothies prepared for players — and it all points back to football, performance and winning.

“It’s funny, I’ve been around Coach Kelly for five years and I don’t know that I’ve ever sat down and just talked with him,” said wide receiver Will Murphy, who played for Kelly at the University of Oregon.

No time to talk. There’s always another drill. Always more film. Always something new to install. There’s a pedal-to-the-metal rhythm that dominates everything around the Eagles’ complex, where Kelly is trying to turn around a 4-12 football team and do it quickly. Even at practice, it’s barely football they’re playing; there’s no huddling, no tackling, no breaks.

“Fastball,” said tackle Jason Peters, a 10-year veteran. “That’s all I can say, fastball. Come watch us on Sundays, and it’s going to be definitely different.”

The Post Sports Live crew debates whether the Redskins are the definitive favorites to win the NFC East. (Post Sports Live)

But what exactly it will look like — even Kelly isn’t certain. The offense will depend largely on the quarterback, one who Kelly isn’t ready to anoint. The defense will depend largely on how quickly players adapt. And the roster will depend on who can forget everything they’ve ever known and fully digest Kelly’s vision.

“Like everything we’re doing, it’s got to be a personnel-driven deal,” Kelly said. “Let’s play to their strengths. We keep finding out every day when we get on the field what they do really well.”

Newly retired quarterback Donovan McNabb stopped by the team’s first full practice of training camp over the weekend. Along with about 30,000 fans at Lincoln Financial Field, he watched the pieces whirl in front of him and tried to decipher Kelly’s exact plan. His verdict?

“I don’t know what they’re doing. I couldn’t tell you,” McNabb said. “I’m sure Chip has a better understanding.”

‘A hard transition’

“He does not care about what the outside world thinks,” said a veteran lineman. “He’s going to run his ship the way he sees fit to run it.”

“With all due respect to what we had last year, it’s just a different approach from the head guy all the way down to the coordinators,” said a veteran safety.

“He’s all business,” said a rookie defensive end. “You could tell he’s got a job and he’s getting after it.”

The Post Sports Live crew debates whether the Redskins’ defense will be more susceptible to the run or the pass. (Post Sports Live)

That’s what players said at the time about Steve Spurrier, Bobby Petrino and Nick Saban — a small part of a long list of college coaches who tried to force their unique systems on the NFL and found that square pegs don’t always fit into round holes.

Time will tell whether Kelly’s methods, which were good enough for a 46-7 record in four seasons at Oregon and have buoyed hopes around Philadelphia, will work at the professional level. The early reviews in training camp have been positive even if it requires a painfully long learning curve for nearly everyone in green.

“If people could pick it up like that, then everybody would do it. . . . It’s a hard transition,” Kelly conceded.

Change in Philadelphia has been fast and immediate. After 17 years at Lehigh University, Kelly moved training camp to the Eagles’ home facility. He’s utilizing science and technology in ways the NFL has barely considered. His camp practices are divided into 21 breakneck sessions and require players’ full attention at all times.

“You have to stay super focused, especially when you’re tired,” said rookie defensive lineman Isaac Remington, who played for Kelly at Oregon. “You got to keep focused and do your job.”

How comparable is it to what Kelly did at Oregon? His Ducks-turned-Eagles say the similarities are striking. The structure is basically the same. Drills and routes very similar. The pacing and the tempo haven’t changed a bit, though some of the terminology and signaling is new.

Kelly hopes it all translates into a regular season output that might be unlike anything the NFL has seen. To wit: NFL teams averaged 64 offensive plays per game last season; Kelly’s high-octane Oregon squad averaged 83.

Defensive players are slowly transitioning from a Wide-9 4-3 base to a 3-4 front and coaches promise to use multiple fronts in the interim. And the offense is installing new pieces every day. “It’s exotic,” Peters said. “Lot of people moving around.”

The team lost fifth-year wide receiver Jeremy Maclin to an anterior cruciate ligament injury last week, but still has a talented corps of tight ends and running backs. Kelly’s Oregon teams ran the ball two out of every three snaps — far more than any NFL team the past four years — and should benefit this season from a healthy, experienced offensive line.

The team tinkered with three tight-end sets earlier this week. The same day, LeSean McCoy, Philadelphia’s fifth-year running back, found himself lined up outside at times, running pass routes. While confusing for offensive players still adjusting, in time the Eagles hope the different formations will confuse opposing defenses even more.

“It’s different,” McCoy said, “But I’ll get to it.”

Quarterback conundrum

It all revolves around the quarterback. No one in Philadelphia knows who will line up under center when the Eagles open the season Sept. 9 against the Washington Redskins. Owner Jeffrey Lurie says he knows how lucky he was to have McNabb hold down the spot for 11 straight seasons. Michael Vick has started 35 games the past four.

There are five players wearing red quarterback jerseys in camp, and any one of three men could start Week 1: Vick, Nick Foles or possibly rookie Matt Barkley, the team’s fourth-round draft pick. The stakes are high, and for at least Vick and Foles, their future with the organization could be at stake. If Foles wins the job and Vick is somehow retained as a backup, the Eagles would be spending $7 million for someone to hold a clipboard on Sundays.

“Everyone came in here, one of the things they appreciate from all of us, they all have a clean slate,” Kelly said. “You get to show us every single day what you can do, where you belong in this thing.”

Kelly is evaluating daily, but the head coach isn’t tinkering with the depth chart each evening. He wants to see how his quarterbacks run the offense in preseason games.

“A quarterback is like a tea bag,” he said, “you don’t know what you’re going to get until the rush is live.”

Kelly’s offensive playbook could then be expanded or contracted based on the victor. While the Eagles are installing the whole system in camp, they might not know the key components until September.

“If I called 20 read options with Nick Foles in the game,” Kelly said, “you should fire me. . . . I think we’ve got to figure out who our quarterback is before we understand the direction of where our offense is going.”

Publicly, the quarterbacks have been saying all the right things — “I love the fact that we’re able to come out here and compete every day,” Vick shared on Monday — but the position battle will loom over the preseason until Kelly sees something he likes. In the meantime, everyone in a red jersey will hear some version of the same question, which has nothing to do with fruit smoothies or the music that provides the soundtrack each day at practice.

“Is this your job to win or lose?” a television reporter asked Vick the other day. The quarterback could only laugh.

“How do you want me to answer that? I can’t answer that question,” he said. “What do you want me to say?”

For now, the Eagles have a lot more questions than they do answers.