Can anyone unseat the Texans in the AFC South?

On the strength of the NFL's top-ranked scoring defense, the Houston Texans captured their second consecutive AFC South title in 2016, despite J.J. Watt missing the majority of the season after undergoing back surgery.

While employing the brutally underwhelming Brock Osweiler at quarterback, the Texans managed to outlast their competition, with a 9-7 record being good enough once again - a testament to the division's mediocrity.

Still, the Texans shouldn't be dismissed as long as they boast one of the league's best defenses. Jadeveon Clowney turned into the player everyone expected after being taken first overall in 2014, Benardrick McKinney quietly emerged as a second-team All-Pro, and the team weathered a storm without their best player in Watt, emerging unscathed.

Can the Titans, Colts, or Jaguars knock off the Texans? There's certainly cases to be made, but the Texans won't go quietly.

Tennessee Titans

Marcus Mariota is developing into a bona fide superstar, and there's an outside chance he could displace Andrew Luck as the division's best quarterback. Few knew what to expect from head coach Mike Mularkey's "exotic smashmouth" offense, but the run game spearheaded by DeMarco Murray and Derrick Henry continually wore down defenders. Tennessee added Corey Davis with the No. 5 pick in the draft to bolster its receiving corps, making it a real sleeper in the AFC.

The Titans solidified their secondary during the offseason, adding Johnathan Cyprien and Logan Ryan, while drafting Adoree' Jackson with the No. 18 overall pick. After Kevin Byard showed flashes of future stardom during his rookie year, the Titans have improved a unit that was once a laughingstock, in an era when five-defensive back sets have become the norm. Tennessee finished tied for 16th in scoring defense last year, and, after making some subtle tweaks, it wouldn't be a huge surprise if it finished in the top 10 this year.

Since general manager Jon Robinson was hired in January 2016, the club has reversed its trajectory. The division is up for grabs, and the young, upstart Titans should be in contention for the entire season.

Indianapolis Colts

Will Andrew Luck be healthy in time for the regular season? That question needs to be addressed before anyone can map the Colts' upcoming season in earnest.

Luck underwent shoulder surgery after the season and still hasn't been cleared to throw. The Colts quarterback has elevated some decrepit offenses in years past, but if he's not healthy, the team's margin of error evaporates. T.Y. Hilton boasts the world-class speed to take over games, but it's hard to forecast the offense's output without Luck.

The Colts may have snagged the steal of the draft when Malik Hooker fell to No. 15. Hooker will be counted on to make an immediate impact, aided by fellow rookie cornerback Quincy WIlson and veteran standout Vontae Davis. Indianapolis also made a few astute signings among its front seven, adding Johnathan Hankins, Jabaal Sheard, and Margus Hunt in free agency. It may not be enough, however.

Indianapolis' success is directly linked to the health of Luck's shoulder, and it's too early to project if he'll be the same. If he's healthy, the Colts should make a serious push for the playoffs; if he isn't, they could be angling for a top-eight pick.

Jacksonville Jaguars

After developing a reputation for performing worse than the sum of their parts would indicate, the Jaguars fired head coach Gus Bradley, who compiled a cumulative 14-48 record. After promoting Doug Marrone to head coach, will the Jaguars continue to be among the NFL's most underachieving teams?

Blake Bortles is the starting point in any assessment of the Jaguars, as he's thrown 51 interceptions through three seasons. The 25-year-old boasts NFL-caliber arm strength, but he's still wildly inaccurate, and has yet to show that he can remain composed throughout the season. If Bortles can make a leap in his fourth year, elevating a passing game that includes Allen Robinson, Allen Hurns, Marquise Lee, and rookie Dede Westbrook, the Jaguars could sneak up on the division. If he can't, they may live and die by his turnovers.

Leonard Fournette, selected fourth overall in this year's draft, provides the Jaguars with the every-down back they've so desperately needed. Fournette's been on the national radar since he was a New Orleans high school prodigy, but it may be too much to ask him to replicate a rookie season in the vein of Ezekiel Elliott.

The Jaguars' defense always appears promising on paper, and this year is no different, after they added standouts Calais Campbell and A.J. Bouye in free agency. Bouye and Jalen Ramsey could quietly develop into one of the NFL's best cornerback pairings, while Telvin Smith and Myles Jack sneak under the radar at linebacker. Is it too good to be true once again?

Bortles will ultimately direct the state of the franchise. If he can reduce his turnovers, the Jaguars have a shot at upsetting the division. If not, it's back to the drawing board.

Also from this series

• Can anyone unseat the Cowboys in the NFC East?
• Can anyone unseat the Packers in the NFC North?
• Can anyone unseat the Falcons in the NFC South?
• Can anyone unseat the Seahawks in the NFC West?
• Can anyone unseat the Patriots in the AFC East?
• Can anyone unseat the Steelers in the AFC North?
• Can anyone unseat the Chiefs in the AFC West?