Before we begin, an important disclaimer: Tony Romo is not dead. Romo -- and the Cowboys' season -- remains intact.

Anyway ... two dress rehearsals took place on Thursday night. One game included two teams, the Dolphins and Falcons, that shouldn't factor into the playoff race. Another game featured two NFC foes, the Cowboys and Seahawks, that figure to be playing deep into January.

As expected, it was the latter game that mattered more. Ezekiel Elliott shined in his preseason debut, Dak Prescott kept on streaking, Russell Wilson performed some live magic, and Romo's night went like this:

Tony Romo suffered a back injury Thursday night. USATSI

Let's break it all down from Miami's 17-6 win and Seattle's 27-17 victory. Here are eight takeaways from Thursday night, also known as dress rehearsal night to everyone not named Bill Belichick.

1. Tony Romo goes down

On the Cowboys' third offensive snap of their third preseason game, their season nearly ended. Romo, who missed 12 games last year, suffered a back injury when he was sacked from behind by Cliff Avril.

He did not get up.

So, Jerry Jones did all that he could. He prayed.

Romo eventually walked off the field under his own power. After speaking with team doctors, he moved around on the sideline and threw the ball. He even requested that his coach, Jason Garrett, put him back in the game.

Garrett declined Romo's offer, which makes sense. The Cowboys went 1-11 last year in the games that Romo missed with collarbone injuries. They went 3-1 with him under center. Keeping him healthy is the key to their entire season.

"We don't think it's a serious thing," Garrett said at halftime, per The Dallas Morning News.

And Jerry Jones began breathing again.

2. Dak Prescott is the Cowboys' insurance plan

When Garrett kept Romo on the sideline, he held the door open for Dak Prescott to continue his torrid preseason. And Prescott didn't disappoint. In all, Prescott went 17 of 23 for 116 yards and a touchdown against a Seahawks' defense that featured starters like shutdown corner Richard Sherman, and key linebackers K.J. Wright and Bobby Wagner. He added 12 yards on two carries to his totals.

His touchdown to tight end Jason Witten, however, was all about Jason Witten, who plucked an under-thrown ball away from Wright.

And his offensive line certainly did its job.

Still, the story of the Cowboys' preseason belongs to Prescott.

Earlier this week, Jones said he wouldn't be pursuing a veteran quarterback to backup Romo. That appears to be a smart move.

Yes, it's only the preseason, but Prescott's set the league on fire in the chances that have been given to him. Entering the game, Prescott had completed 22 of 27 passes, racked up 338 passing yards, and scored four passing touchdowns and two rushing touchdowns. Still, he has yet to throw an interception.

Will Brinson might've been underestimating the power of Prescott when he said 10-15 percent of the Cowboys' fanbase is secretly hoping the team is forced to start him over Romo.

Fifty percent, for sure.

3. Ezekiel Elliott officially arrives

The Cowboys struck gold with Ezekiel Elliott. I don't care if we've seen him play in just one quarter of a preseason game. He's the real deal. Barring an injury, he's going to win Rookie of the Year.

Against the Seahawks, Elliott picked up 48 yards on seven carries, which means he averaged a nice 6.9 yards per carry. Lost during Romo's injury was the block Elliott put on Wright, which allowed Romo to escape a collapsing pocket.

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Then, of course, there was his running. And his power, as he lowered the boom on Seahawks safety Kam Chancellor.

Ever since the Cowboys drafted Elliott with the No. 4 overall pick in the draft, we've only been able to imagine how the Ohio State runner would fit behind arguably the league's best offensive line. Finally, on Thursday, our fantasies were replaced with real game footage.

Our impossibly high expectations didn't ruin the experience.

4. Russell Wilson: Still good

This isn't exactly breaking news, but Seahawks quarterback Russell Wilson is still a wizard capable of performing live magic tricks in front of thousands of fans.

Trick No. 1:

Trick No. 2:

Wilson ended up posting a 135.4 passer rating by completing 16 of 21 passes for 192 yards and those two touchdowns. After his incredible second half of the season a year ago and his impressive outing Thursday, we shouldn't rule him out as a legitimate MPV candidate.

5. Arian Foster doesn't look finished

Arian Foster, released by the Texans in March, remained a free agent until mid-July when the Dolphins scooped him up. On Thursday, Foster made every other running back needy team around the league look silly, even if he only gained 10 rushing yards.

Foster didn't start in the backfield with Ryan Tannehill. The starting job fell to the younger Jay Ajayi. But once Foster was given the chance to prove that he's not completely finished despite his age (30) and injury issues (torn Achilles), he proved that he deserves to be starting when the Dolphins open up the regular season in Seattle.

Foster entered the game on the Dolphins' 14th offensive snap of the night. He danced around the Falcons' secondary to notch a first down on a first-quarter reception.

That's important when considering Adam Gase's fondness for the no-huddle offense, which limits the Dolphins' ability to sub in fresh players on a given drive. So, the running back on the field will be expected run, catch, and block. If a drive is operating as planned, the Dolphins won't have time to swap in a pass-catching back on a critical third down. Foster's reliability as a pass catcher shouldn't be overlooked.

Neither should his ability to cut up a defense. In the second quarter, he scored his first touchdown with the Dolphins, using a sharp juke to gain entrance into the end zone.

Arian Foster is alive and well, even if Ajayi accumulated more total snaps Thursday.

6. Ryan Tannehill: Flashes of improvement

When the Dolphins' began the game at their own 12-yard line and marched to the Falcons' side of the 50 on six no-huddle plays, the Adam Gase hype registered an 8.7 on the unofficial 1-to-Christine Michael hype scale. Did Gase already fix Ryan Tannehill?

Tannehill, a fast and athletic quarterback who rushed for a career-low 141 yards last year, picked up 22 yards on the first offensive snap. It was the kind of play that Gase ran with Jay Cutler in Chicago on a game-by-by basis to keep defenses off balance, except it served as more than just a changeup with Tannehill.

It turned into an explosive play.

Tannehill completed three short passes to his targets with ease. Again, this looked similar to the Bears' offense last year, which turned Cutler into an efficient and risk-free quarterback.

And then, the buzz died. The Dolphins' drive ended with a Tannehill interception.

That pick, though, came via a deflection at the line of scrimmage -- a fluky play that ended a promising drive.

Unfortunately, the back-breaking mistakes continued for Tannehill. He (again) looked efficient at the beginning of the team's second drive, completing his first few passes. And then, the mistake (again). Dealing with pressure up the middle, Tannehill launched a late throw off his back foot to his receiver, who was running a comeback route down the right sideline. The ball should've been picked off by Desmond Trufant (again). The drive concluded a play later with another incompletion.

The point being, while Tannehill in Gase's offense actually looked really darn efficient at times on Thursday night, he also made the kind of mistakes that effectively render those efficient completions pointless.

In one half of action, he went 20 of 29. That's good! He also averaged 5.3 yards per pass and the Dolphins scored seven points. That's not good.

To be clear, Tannehill didn't look bad. He just didn't look fixed, at least not yet. And that's OK. It's still August. But the Dolphins are clearly a work in progress -- an inconsistent team -- that probably won't compete for a playoff spot.

7. Matt Ryan: Bleh

The Dolphins should feel better than the Falcons, though, because Matt Ryan did nothing to ease their concerns after his disappointing 2015 campaign.

On Thursday night, Tannehill showed flashes of improvement. Ryan did not. He went 12 of 22 for 129 yards and an interception. His passer rating? 53.0.

The pick occurred in the red zone, where he was intercepted four times last season.

He also struggled under duress.

His arm resembled Peyton Manning's arm of 2015. His deep passes floated and lacked zip.

So no, Ryan did not look good.

8. Injury scares

Romo wasn't the only star to suffer a scare:

On Thursday night, all four teams survived. And that's all that really matters in the preseason.