5 Instant Takeaways: Miami Dolphins lose to New York Jets, 40-17

Teddy Bridgewater's first career Dolphins start lasted only one play in a 40-17 loss at the Jets on Sunday.

Bridgewater was sidelined by the NFL's new concussion protocols after taking a hit from New York rookie Sauce Gardner that resulted in an intentional grounding and safety.

Bridgewater, the Miami native, was relieved by rookie Skylar Thompson.

The Dolphins said Bridgewater passed concussion tests. But a spotter at the game said Bridgewater showed signs of ataxia, which is abnormality of balance, stability, motor coordinator or speech.

Game recap: Looking back at Dolphins vs. Jets

Skylar Thompson steps in: Skylar Thompson in at quarterback after Teddy Bridgewater hurt

Teddy Bridgewater injury: Dolphins QB Teddy Bridgewater ruled out of NY Jets game after spotter says he stumbled; in concussion protocol

Tua Tagovailoa is out indefinitely following a concussion sustained in the previous game. It's unknown when Bridgewater will return, but he will undergo further evaluation this week.

Thompson, a seventh-round pick from Kansas State, performed decently. However Thompson lost a fumble in the fourth quarter that led to a critical Jets touchdown. At the time, Miami was traliling 26-17.

Injuries are a mounting concern for the Dolphins. Left tackle Terron Armstead left and did not return with a toe injury. Tyreek Hill and Durham Smythe left the game with injuries.

Miami played this game without starting cornerbacks Byron Jones and Xavien Howard.

Miami's defense, despite key injuries, should be playing better than it did on Sunday. In fact, it should be playing better over the course of the first five games.

After a 3-0 start, Miami has dropped two in a row to fall to 3-2.

The Dolphins trail Buffalo (4-1) and the Jets (3-2) in the AFC East.

New York snapped a 12-game losing streak to AFC East opponents, and a four-game losing streak to Miami.

Here are five takeaways:

Keeping Skylar Thompson was smart

After Thompson led the NFL in preseason passer rating and touchdowns, it seemed obvious Miami should keep him on the roster as a third quarterback.

That decision has now become very clearly a smart one. Last week, Tua Tagovailoa sustained a concussion. After being sidelined by newly adjusted protocol after only one play on Sunday, Teddy Bridgewater will need to be cleared this week in order to play against Minnesota.

In fact, it seems every NFL team should strongly consider carrying three quarterbacks on their roster now. At worst there has to be a third quarterback on practice squad.

Thompson is a 7th-round pick. But he has a strong arm. He has mobility. He has confidence. He's not the typical rookie as he's 25 years old.

Keeping him on the roster was the right decision. And based on what we saw in the spring and summer, Thompson also appears to have been a wise draft pick.

Mostert gets ground game going

Raheem Mostert has a familiarity with the Dolphins' outside zone scheme and also has good vision and makes good decisions.

And so even though Chase Edmonds was signed to be the Dolphins' top back and paid a lot of money, it's not shocking that Mostert is emerging.

In the first half on Sunday, Mostert rushed for 77 yards and a touchdown. In the second half, he went over 100 rushing yards. Miami's rushing attack had struggled through the first four games of the season.

As Mostert has noted, Miami's scheme is fairly complex. And so it makes sense that a player with experience in the system is excelling.

Mostert, who played briefly for Miami early in his career, emerged as an elite rusher playing for the 49ers, where coach Mike McDaniel was an offensive assistant.

Edmonds has also not been as effective or consistent as a pass-catcher as had been hoped.

Dolphins go without Pro Bowl CBs

Jets running back Breece Hall hauled in a long completion in the second quarter on an apparent coverage bust. It's possible veteran safety Eric Rowe was involved in the coverage mix-up.

Miami played without Pro Bowl cornerbacks Howard and Jones. Howard tested injured groins in pre-game but it was determined he could not go.

Thus, Miami leaned on undrafted cornerbacks Kader Kohou and Nik Needham, who are among the best finds by the club in recent years. There were ups and downs.

In general, the Dolphins' pass defense needs to improve. But with Kohou, Needham and keion Crossen, there is decent depth. Former first-rounder Noah Igbinoghene even played some, though he did not appear to make a positive impact.

Terron Armstead injury impact

Pro Bowl left tackle Terron Armstead left with a toe injury in the first half and did not return. Brandon Shell, who was activated to the roster before the game, slid in at left tackle.

Shell does have plenty of NFL starting experience. But the loss of Armstead for any period of time could be really devastating. Consider Miami has been playing without right tackle Austin Jackson.

Armstead protects the blind side for both Bridgewater and Thompson. And he's the stabilizing, veteran leader of the group.

On Sunday, young veteran Greg Little had some tough moments at right tackle. He's been solid there. But he's said he feels more comfortable at left tackle. In this game he was beaten for a sack and committed a false start.

Miami's offensive line has been below-average with Armstead. WIthout him, it's a very serious concern.

This & That

Melvin Ingram has been good for the Dolphins, but he did commit his fourth penalty of the season in the first half. After two offsides, Ingram now also has two facemask penalties this season... Excellent creativity from coach and play-caller Mike McDaniel with a direct-snap to tight end Durham Smythe, resulting in a short touchdown run. On the play, Thompson was told to wave his arms and act as if he was having a hard time getting the play call in. Smythe began the play lined up outside the right tackle in the formation... . Tyreek Hill was sent into the game as a punt returner at the end of the third quarter, with Miami trailing 19-17. That's the type of spot Miami is obviously willing to utilize Hill... Defensive coordinator Josh Boyer unveiled a unique third-down package in which only three players rush and a slew of Dolphins line up near the first-down marker. On that play, rookie Channing Tindall made the tackle to force a punt... Rookie tight end Tanner Conner had a critical fourth-quarter drop. At the time of that drop, Mike Gesicki had been targeted once for no catches... Jason Sanders missed a 54-yard field goal in fourth quarter.

Joe Schad is a journalist at the Palm Beach Post part of the USA TODAY Florida Network. You can reach him at jschad@pbpost.com. Help support our journalism. Subscribe today.

This article originally appeared on Palm Beach Post: Miami Dolphins lose to Jets as Teddy Bridgewater lasts one play