The 2019 NFL season is quickly unfolding and we are beginning to see which teams are legitimate and which ones are fraudulent. With that in mind, let's reflect on what we've seen in the NFL to this point of the season.

First and foremost, the New England Patriots are showing once again that they aren't leaving anytime soon. Bill Belichick's squad has gotten off to a blistering 5-0 start and his defense is stifling teams to just 6.8 points per game this season.

On the other end of the spectrum, there are still four teams who are searching for their first win of the season. The winless teams that remain in the NFL include the Miami Dolphins, Cincinnati Bengals, Washington Redskins, and New York Jets.

None of those teams that were just named had any sort of expectations entering the season. Therefore, they won't be listed among the most disappointing teams in the NFL thus far.

Instead, we will highlight a few teams who haven't lived up to the expectations that were given to them prior to the beginning of the season. Without further ado, here are three teams in the NFL who have underwhelmed through the first five weeks.

3. Tennessee Titans (2-3)

When Andrew Luck abruptly announced his retirement from the NFL, the Tennessee Titans were talked about as a team in the AFC South who could take control of the division. Unfortunately, the first five weeks haven't gone according to plan.

Entering the year, there were question marks surrounding Marcus Mariota as he enters the final year of his rookie contract. Similarly to previous seasons, Mariota has been hot and cold to begin this season for the Titans.

Tennessee has imposed its will on defense, boasting the fifth-best defense in terms of points allowed (15.2). But on the other side of the ball, the offense is posting just 19.6 points per game (ninth-worst in the NFL).

With the inconsistency on offense, the Titans are currently 2-3 and sit at last place in the AFC South. If Mariota continues to be erratic, we may see Ryan Tannehill at some point this season.

2. Denver Broncos (1-4)

The Denver Broncos entered this season as a team that was expected to improve upon a 2018 season where they went 6-10. After the 2018 season concluded, John Elway believed his team was a new coach and quarterback away from getting back to the postseason.

As a result, he fired Vance Joseph and replaced him with Vic Fangio; a defensive-minded coach. Also, the Broncos replaced Case Keenum with Joe Flacco as the team's signal-caller. Elway expected everything to go along smoothly to begin the season but that hasn't been the case.

Thus far, Flacco has thrown for 1,258 yards, six touchdowns, and four interceptions. Flacco hasn't been terrible but the offense hasn't been able to put it all together. To begin the season, the offense is scoring just 18 points per game (tied for sixth-worst in the NFL).

On the other hand, the defense lost Bradley Chubb for the rest of the season and Von Miller hasn't been able to wreak havoc by his lonesome. Putting all of that together, the Broncos are 1-4 and there are reports that the team could begin trading players to acquire draft picks for the future.

1. Atlanta Falcons (1-4)

Ever since blowing a 28-3 lead to the Patriots in Super Bowl 51, the Atlanta Falcons haven't been able to get back to being a contending team in the NFL. However, during the offseason, there were murmurs that this Falcons team could revert them back into contention in the NFC South.

Prior to the season, Dan Quinn fired both of his coordinators and assumed the role as the team's de facto defensive coordinator. For the offense, Dirk Koetter was expected to get all of Atlanta's weapons back into Super Bowl form.

When you have Matt Ryan, Julio Jones, DeVonta Freeman, Calvin Ridley, Mohamed Sanu, and Austin Hooper on offense, you'd expect points to be easy to come by. On the contrary, that group has managed to score just 20.4 points per game this season.

Along with the offense underperforming, the defense hasn't fared much better with Quinn calling the plays. In Week 5, the Falcons surrendered 592 yards and 53 points to the Houston Texans. With everything going awry, Atlanta stands at 1-4 at this point of the season and the seat is getting hotter for Quinn.