FLORHAM PARK, N.J. -- Dan Cooper knows Teddy Bridgewater's heart like few people do, because Cooper cut open the quarterback's leg on Sept. 8, 2016, when pro football's most stunning comeback began inside a Dallas clinic.

Amputation was no longer a feared possibility, and yet what the surgeon faced that day was something one might see on the set of a sci-fi film.

"It was just a horribly grotesque injury," Cooper said.

The good doctor was talking about the quarterback's left knee, which had exploded without warning nine days earlier while Bridgewater was dropping back to pass, untouched, in a Minnesota Vikings practice.

"It's mangled," Cooper said. "You make the skin incision, and there's nothing there. It's almost like a war wound. Everything is blown."

Bridgewater could get traded by the New York Jets to clear room for the No. 3 overall draft choice, Sam Darnold, to start on opening day; the Jets likely won't want to pay Bridgewater $5 million as a backup with Josh McCown already on the books for $10 million. In fact, Friday's preseason meeting with the Giants could be the last chance for New York-area fans to see the former Vikings Pro Bowler as one of their own.

Bridgewater might go without taking a single regular-season snap for the Jets, who have seemingly spent a half-century searching for a young star at the sport's most crucial position before ending up with two viable candidates for the role at the same time.

Sam and Teddy. Teddy and Sam. The Jets are apparently going with Darnold, which likely means a new address for Bridgewater sooner rather than later. Either way, New Yorkers should understand what they're looking at while they still have the chance. Bridgewater is a not-so-minor miracle, a walking advertisement for the power of the human spirit.

"This surgery was an absolute gut test, a test of what you're made of, and I've seen it break people down," Cooper said. "I never saw it break Teddy down. ... Most people have no idea the volume of the workload this kid had to put in. He had a toothpick of a leg he had to rebuild."

Bridgewater gave his doctor permission to talk to ESPN.com about the surgeries -- there were two -- that granted him access to a second NFL life. Cooper, the Cowboys' team physician, remembered the first surgery lasting about 4½ hours, and the second one -- eight weeks later to treat stiffness around the knee -- lasting about an hour. Both were performed in the Carrell Clinic in Dallas.

Just being on the football field is enough to make Teddy Bridgewater smile. Elsa/Getty Images

Bridgewater had been referred to the surgeon by former Cowboys coach Bill Parcells, who had become something of a father confessor to the quarterback. Parcells told the doctor that Bridgewater was one of the greatest kids he'd ever met.

Truth is, Bridgewater was the Vikings' Darnold only a few years ago. He was the young and poised franchise quarterback-to-be, a prospect who had 15-year starter written all over him. And then suddenly on Aug. 30, 2016, during a simple noncontact drill 25 minutes into practice, Bridgewater went down in a heap. Teammates and coaches reacted the way teammates and coaches reacted to the gruesome leg injuries suffered by the likes of Joe Theismann, Kevin Ware, Paul George and Gordon Hayward.

They screamed. They cursed. They recoiled. They prayed. An ambulance with sirens blaring raced into the complex to transport away a 23-year-old athlete who was afraid doctors might need to amputate. Vikings coach Mike Zimmer immediately canceled practice. He worried that Bridgewater would never walk again, never mind play again.

"This surgery was an absolute gut test, a test of what you're made of, and I've seen it break people down. I never saw it break Teddy down. ... Most people have no idea the volume of the workload this kid had to put in. He had a toothpick of a leg he had to rebuild." Dan Cooper, Teddy Bridgewater's surgeon

The coach grew emotional that day when talking about the devastating injury, even referencing the unexpected loss of his wife in 2009. Zimmer said he leaned on a spiritual connection with his late father and on the secular bond he shared with his professional mentor, Parcells.

The Vikings' training staff and first responders stabilized Bridgewater, who did not suffer the kind of arterial or nerve damage that could've cost him his leg.

"But it's certainly the worst knee dislocation in sports I've ever seen without having a nerve or vessel injury," Cooper said. "It's an injury that about 20-25 percent of NFL players are able to come back from. ... It's a horrific injury. You've torn every single thing in your knee and it's hanging on by one ligament on one side like a hinge."

Cooper performed a reconstruction of Bridgewater's anterior cruciate ligament. "And then everything on the lateral side of his knee was reconstructed, about five ligaments over there," the surgeon said. "We repaired them, then took one of his own hamstring tendons and transplanted it to the lateral side of his knee."

The experience was incredibly stressful for a doctor fully invested in his patients. And yet over and over, Cooper maintained that his repair work in such cases is effectively complete on Day 1, and that the athlete is left with overwhelming emotional and physical burdens that he or she has to manage every day for a year or more. In the immediate wake of his injury, Bridgewater said in a statement, "I come from amazing DNA, I watched my mom fight and win against breast cancer. We will, as a team, attack my rehab with the same vigor and energy."

Bridgewater made a stirring return to the field in Minnesota last December, throwing his only two passes of the season in a blowout victory over Cincinnati. The Vikings belonged to Case Keenum by then, and soon enough they would belong to Kirk Cousins. In March, after the Jets signed Bridgewater to a one-year, $6 million deal, Zimmer said reports from Vikings doctors on his former quarterback's recovery "weren't as positive" as he'd hoped.

Cooper was on a plane when Bridgewater made his preseason debut for the Jets against Atlanta, so he had a Dallas video staffer tape the game for him. When the surgeon sat down to watch, he was profoundly touched by the images of Bridgewater completing 7 of 8 passes for 85 yards and a touchdown. The Jets won 17-0, and nobody dared tell Cooper that this preseason result was meaningless.

"I've always said Super Bowls for surgeons don't happen in February," he said. "It was an incredibly gratifying thing for me to see a player overcome that. ... That's exactly why I do what I do, to see Teddy play like he did."

It was a gray and drizzly Sunday morning, the kind that begs you to stay in bed, and early on Bridgewater was wearing the body language of a man who wished he'd done just that. The Jets were running through a two-hour practice in front of a small but spirited gathering of fans, and Bridgewater wasn't matching the energy of the hotshot rookie, Darnold, who bounced about the field as if he had just been awarded the starting job for keeps.

Bridgewater looked as if he'd just gotten word of Darnold's appointment, too. He threw one touchdown pass on an out-and-up to Andre Roberts near the left sideline, and in congratulating his fellow quarterback by slapping his hand and helmet, Darnold appeared more excited about the pass than the man who delivered it. Then the first-rounder from USC took the field with the first-stringers, while Bridgewater faded into the background with the subs.

Sam Darnold, background, is one of many Jets in awe of Teddy Bridgewater, calling the quarterback "a cool cat." Tony Quinn/Icon Sportswire

Teddy knew. So did McCown, the 16-year vet. Everyone with a functioning pair of eyes and a keen sense of how things work in the NFL knew that the Jets had already decided, after two preseason games, that there was no point in redshirting the redhead. Barring something unforeseen, Darnold was going to be their Week 1 guy.

Todd Bowles and his offensive coordinator, Jeremy Bates, have raved about Darnold's maturity and presence, but they have also expressed a certain degree of awe over what Bridgewater has already accomplished. Bowles said that the former Louisville star is forever smiling and projecting the vibe of a perfectly healthy player.

"He's never showed me that he was injured," Bowles said.

Bates said he had goosebumps on the sideline when Bridgewater entered the game against Atlanta.

Darnold? He called his chief competition "a cool cat" with an even disposition who's always telling him, "Hey, bro, we're out here playing football. Doesn't really get much better than that."

In his second preseason game, against Washington, Bridgewater completed 10 of 15 passes for 127 yards and another touchdown to go with his first interception and some hits he said he absorbed "for my own benefit. It's something that I wanted to do and it just showed me that, 'Hey, you're good.'"

Yes, he's very good. Though Darnold has been impressive, Bridgewater has slightly outperformed him over these two games. His former offensive coordinator at Louisville, current University of Pittsburgh assistant Shawn Watson, watched Bridgewater against Atlanta and Washington and came away believing he was whole. Watson saw a quarterback whose rhythm and ball location were exactly as they were before the injury.

"I see Teddy," Watson said. "I see the old Teddy. I see the guy I coached at Louisville."

Bridgewater feels like that player, too. He said the other day that it was fun running gassers and getting in shape, and that he hasn't been held out of any drills. He shrugged off questions about trade rumors, and who could blame him for refusing to sweat the small stuff?

"His inner resolve kept him from being defeated on a daily basis for a year and a half." Dan Cooper, Teddy Bridgewater's surgeon

"I am blessed with the opportunity to continue to do what I love to do," Bridgewater said. "That's what's most important to me right now. Just waking up every day knowing that I get to continue to play football."

The following day, at the end of that otherwise sluggish Sunday morning in the rain, Bridgewater suddenly sprang to life on his final drive and fired a strike over the middle to Jordan Leggett for a walk-off touchdown to end practice. To celebrate the moment, the quarterback playfully and repeatedly jumped on the back of a defensive tackle. Teddy Ballgame was back.

So far it's been a hell of a comeback. Built like a one-iron, Bridgewater has proved to be one of the strongest men in the NFL.

"His inner resolve," Cooper said, "kept him from being defeated on a daily basis for a year and a half."

He might get traded anyway, and that's OK. Teddy Bridgewater doesn't need to take any regular-season snaps with the Jets. He has already left a mark on a tough town that won't soon forget him.