The most significant and gut-wrenching play of the NFL preseason happened on Tuesday. In practice. On a non-contact play.

Young Vikings franchise quarterback Teddy Bridgewater suffered no ordinary knee injury. The team said he suffered a dislocated knee, a torn ACL, and other structural damage after he crumpled into a heap 25 minutes into practice. The injury was so gruesome that the Vikings immediately called 911 and Bridgewater was taken via ambulance to Hennepin County Medical Center — not the closest hospital but the premier trauma center in the Twin Cities. Coach Mike Zimmer canceled practice for the rest of the day. One league source said he heard from several players who were in tears after practice.

“In my 17 years with the Chargers, we never had an ambulance come,’’ said orthopedic surgeon David Chao, San Diego’s team doctor from 1997 to 2013. “I’ve never had a 911 call for a football player injury.’’

Fortunately, Bridgewater’s injury was not as devastating as it could have been. The Vikings announced that Bridgewater did not suffer arterial or nerve damage.

But Bridgewater is looking at a major rehab over the next year-plus, and his career was just thrown a significant curveball.

“In order to have a testimony, you have to have a test,’’ 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. My faith is strong, my faith is unwavering, and my vision is clear. My purpose will not be denied.’’

For those of us who didn’t go to medical school, Bridgewater’s injury conjured a few overarching questions. How does this happen? How can a player have his knee literally fall apart on a non-contact play? And just how common is this?

“Fortunately, it’s rare,’’ said Chao, whose 20-year NFL tenure also included stints with the Vikings and Bears. “There had to be something that happened that we don’t know yet, whether somebody ran into him, whether it was a botched play, something slipped. It’s a perfect storm of being off balance, your knee is in a funny position, and your muscles not contracting to control it while your foot is stuck in the ground.

“Thousands of times a day you walk up a step or off a curb and you’re fine. But if you don’t know that step is coming, sometimes it startles you and strains your back. That’s what this was, but much worse and at full speed.’’

Considering that Bridgewater dislocated his knee, Chao explained that Bridgewater tore at least two knee ligaments, possibly three, and potentially even all four (the ACL, MCL, PCL, and LCL), though the last scenario is unlikely considering it was non-contact.

The NFL sees dozens of non-contact knee injuries every year, and a handful of multi-ligament injuries, but Bridgewater’s is far more severe and fortunately more rare. It’s potentially worse than the multi-ligament injury suffered by former running back Marcus Lattimore, which prevented him from ever playing an NFL snap. And it was more severe than the knee injury suffered by former Notre Dame linebacker Jaylon Smith, who was able to watch the rest of the game while standing on the sideline. Lattimore and Smith suffered subluxations, not a true knee dislocation. The difference with Smith, however, is that he reportedly suffered nerve damage, which is a major hindrance for him to return to pre-injury form, while Bridgewater reportedly did not injure his nerves.

Bridgewater was taken to a trauma center to determine if there was arterial damage, which if not fixed immediately could have led to significant blood loss and potential amputation (his artery was not severed).

“The first thing is to make sure the artery is OK,’’ Chao said. “The nerve you can kind of test — wiggle your toes. But the artery is what you worry about, and even though you can feel a pulse you can be fooled.’’

Chao said that Bridgewater’s injury is more comparable to the one suffered by former Patriots running back Robert Edwards, who famously dislocated his knee playing beach football at a Pro Bowl event in 1999 and almost had his leg amputated.

Edwards was never the same after his injury, though he did resume his career with the Dolphins in 2002, and he played in the Canadian Football League through 2007. But even the Edwards comparison isn’t perfect in trying to determine if and how Bridgewater can return.

“Knee dislocations are like saying a major car accident,’’ Chao said. “All major car accidents are not the same. Is the car totaled? Not necessarily. Sometimes you can fix the car back up and drive it again.’’

Bridgewater has two factors working in his favor as he begins a long road to recovery. One, he’s only 23 years old, and his body’s healing powers work well. Two, he plays a position in which elite running skills are not required (just ask Tom Brady).

“If this were Adrian Peterson, I don’t care how great he is as a running back, most likely he’s not returning to play, and if he does there’s no way he’s the same running back,’’ Chao said. “Fortunately, Teddy Bridgewater is a quarterback. I don’t doubt that he will be an NFL quarterback again. I think he can play in 2017. Philip Rivers once played on a torn ACL. But will Teddy Bridgewater be the same quarterback athletically? No, he’s going to lose a step. Let’s just hope it’s a very small step.’’

HITTING CLOSE TO HOME

Checking in on the Patriots

■ Rob Ninkovich’s four-game suspension for violating the NFL’s policies on performance-enhancing drugs won’t hurt the Patriots, and in fact could help them. Ninkovich already was set to miss the first month of the season with a torn triceps suffered in training camp, and the Patriots were going to have to carry him on the 53-man roster and make him inactive on game days.

Now, the Patriots will place Ninkovich on the reserve/suspended list and get to fill his roster spot with a healthy body.

The only person this suspension hurts is Ninkovich. He will lose 4/17ths of his $1.5 million base salary, or $352,941. Like Tom Brady, Ninkovich won’t be allowed to appear at the team facility or have contact with team officials, other than to arrange his rehab. Ninkovich also will have to rehab his injury away from the facility. And there is the notion that Ninkovich’s reputation has been damaged, but the only people who think less of Ninkovich today are the ones naive enough to think that football players don’t use a whole universe of supplements and PEDs to get their bodies in peak physical condition.

The Patriots also will get a salary cap credit in 2016 for Ninkovich’s $352,941, and a $100,000 credit in 2017 for his missed roster bonuses.

■ It was fascinating to watch how the Patriots used newcomer Barkevious Mingo Thursday night against the Giants. He played defensive end, outside linebacker, and inside linebacker, and appeared on four special teams units (both punt and kickoff units). Mingo looks like he can replace Jamie Collins or Shea McClellin in an injury situation. A Browns scout mentioned to us that Mingo is an “excellent special teams player if it doesn’t work out on defense.’’

■ We’re told that several teams called the Patriots over the last week trying to pry second-year tight end AJ Derby from them, hoping that Derby was the victim of a numbers crunch with Rob Gronkowski, Martellus Bennett, and Clay Harbor also at the position. Derby had 15 catches for 189 yards and a touchdown in the preseason and made some impressive catches in traffic. And the Patriots were indeed poking around the trade market for running backs last week, though they didn’t bite on Bishop Sankey and others.

■ Found this quote from Bill Belichick last week to be interesting:

“I think everybody on the team, really their No. 1 focus is to get ready to play football. Our players aren’t coaches, they’re players, and they need to get ready to play, and as I said, I think every player needs to get ready to play . . . I don’t really think players have a lot of time to run around and be telling everybody else what to do. Honestly, there is enough that all of them need to work on individually, and that would be every single player, that’s a full plate for them. I don’t really think that’s their job, and I don’t think any player has enough time to do that because they all have things that they need to do to prepare for the season.’’

Belichick is clearly defending Brady and his lack of interest in being Jimmy Garoppolo’s “mentor.’’ We believe that Brady’s relationship with Garoppolo is professional, and he has nothing personal against him, but Brady is not going to go out of his way to help Garoppolo take his job, either.

DEAL HIM IN

Kraft behind team for Vegas

Speaking of interesting quotes from the Patriots, team president Jonathan Kraft offered some intriguing insight into how NFL powerbrokers view Las Vegas as a potential home for the Raiders.

On the team’s pregame radio show at the Panthers game, Kraft spoke in glowing terms of the Vegas market.

“Las Vegas has really turned itself into a very different place,’’ Kraft said. “It’s almost viewed, after Los Angeles or right alongside Los Angeles, as the entertainment capital of the world. And shouldn’t our country’s greatest sports product, and in my opinion the world’s greatest sports product, shouldn’t it be in the entertainment capital? It makes sense.’’

This was the same thinking the NFL owners used when choosing Stan Kroenke’s stadium/entertainment project for Los Angeles. And even if Las Vegas doesn’t have the biggest home market, Kraft doesn’t believe a Vegas team would have trouble getting fans in the seats.

“Something that Robert [Kraft] absolutely loves to say when everyone asks him about it — the other teams in the AFC West, their fans are going to love it, because every year that’s going to be the road trip they all plan on going to,’’ Kraft said.

We still think that the ultra-wealthy and tech-savvy Bay Area makes far more sense for the Raiders than does Vegas. But if Las Vegas is able to come up with a stadium plan and the Bay Area isn’t, the NFL sees plenty of positives in the Vegas market.

“The real critical thing if a team is ever to move there, obviously, is that there’s a first-class facility that gets built and the community really shows that they’re prepared to support the team,’’ Kraft said. “I assume [the support] part would be easy, and they are known for building great buildings, so hopefully that could happen, and then it’s probably a feasible thing.’’

ETC.

Season can be quite a trip

A trip around the globe is approximately 25,000 miles, and five NFL teams will accomplish the imaginary feat. The Rams will travel a league-high 35,952 miles this season, with four games in the Eastern time zone. The Raiders are next at 31,622 miles, followed by the Seahawks (27,766), 49ers (25,668), and Dolphins (25,548). The Patriots are 10th at 19,336 miles.

The Steelers will travel only 5,142 miles this season, as all 16 of their games will be played in the Eastern time zone. The Browns (6,074), Ravens (7,084), Bears (8,766), and Packers (9,050) round out the bottom five.

Unsettling news for some

Retired players are ever closer to receiving their payments from the $1 billion concussion lawsuit settlement with the league, but the estate of player Cookie Gilchrist, who died in 2011, is standing in the way. Gilchrist’s attorneys filed an appeal last week against the settlement because it does not include payments for players who suffer from CTE.

But Gilchrist’s appeal is delaying matters for the thousands of other former players who need the concussion settlement to help pay medical bills. Payments can begin about three months after all appeals are dropped or settled.

“These appeals come with devastating consequences for the thousands of retired NFL players suffering from neurocognitive injuries and effectively stand between truly injured retired players and their sole prospect for obtaining benefits while still alive,’’ attorney Christopher Seeger said in a statement. “While we are pleased several appellants have decided against petitioning the US Supreme Court, it is clear the few lawyers still objecting to this settlement have motives other than what is in the best interest of the retired NFL player community. We hope the Court will reject this appeal and affirm the settlement so former players can finally receive the care and support they urgently need.’’

Extra points

Brutal housecleaning going on in Tennessee under first-year general manager Jon Robinson, a former Patriots scout and executive who is getting rid of former GM Ruston Webster’s picks. Robinson traded Dorial Green-Beckham (2015 second-round pick) to Philadelphia, and released Bishop Sankey (2014 second-round pick), Justin Hunter (2013 second-round pick), and guard Jeremiah Poutasi (2015 third-round pick). We wonder if Robinson could have released these players earlier in the offseason to give them a chance at finding other homes . . . Looking ahead to Week 1, Cardinals coach Bruce Arians said he expects defensive back Tyrann Mathieu (torn ACL) to play every snap against the Patriots, while Texans coach Bill O’Brien said it’s looking more likely that J.J. Watt (back surgery) will be in the lineup against the Bears, as well . . . The US Ryder Cup team visited Gillette Stadium last week, and the Patriots presented each golfer with a Patriots jersey. Everyone got jersey No. 1 except for Jim Furyk, who got No. 58 in honor of his recent PGA Tour-record 58 at the Travelers Championship . . . The Bills-Jets game in Week 2 will be the first to be streamed live on Twitter, in addition to the traditional television broadcast. Patriots-Texans in Week 3 will also be on Twitter . . . Got to love Chip Kelly. Every year, the NFL public relations department asks its head coaches to fill out an “About Me’’ questionnaire as part of its season preview. One question is, “Who has the hardest job in football?’’ Kelly’s answer: “No one, it is a game.’’ We also learn that Kelly’s favorite food is “sandwiches’’ and that if he weren’t coaching, he’d be a fireman.

Ben Volin can be reached at ben.volin@globe.com. Follow him on Twitter @BenVolin. Material from interviews, wire services, other beat writers, and league and team sources was used in this report.