There is less than a week until the floodgates open, as NFL free agency is scheduled to get underway on March 18. Among the divisions in the NFL, the AFC South could be one of the most interesting divisions to keep an eye on in free agency.

For the second straight season, the Texans were able to win the AFC South title. Despite being the best team in the division this past season, Bill O'Brien — who was officially appointed as the team's GM — still needs to fill some holes that reside on the roster.

The Indianapolis Colts are heading into their second season without Andrew Luck under center. After having Jacoby Brissett start for them in 2019, it seems likely that the Colts will add another quarterback this offseason.

As for the Jacksonville Jaguars, they have quite a ways to go before being considered a contender in the AFC South. First things first, the Jaguars need to commit to either Nick Foles or Gardner Minshew next season.

Last but not least, the Tennessee Titans have pivotal decisions to make pertaining to Ryan Tannehill and Derrick Henry. All that being said, here is one player each team in the AFC South needs to sign in NFL free agency.

Houston Texans — Chris Harris Jr.

Throughout the 2019 NFL campaign, it was apparent that the Texans were in dire need of some aid in the secondary. Amid the second half of the season, Houston traded for Gareon Conley and signed Vernon Hargreaves.

Despite adding those guys to the defense, the Texans still allowed over 300 passing yards in four of their final seven contests (including the NFL Playoffs). Provided that, adding Chris Harris Jr. could give Houston some much-needed assurance in their pass defense.

For the past nine seasons, Harris has been one of the most consistent cornerbacks in the NFL with the Denver Broncos. Even though he turns 31 years old in June, Harris would be a remarkable signing for the Texans this offseason.

Indianapolis Colts — Anthony Castonzo

As previously mentioned, the Colts are clearly going to bring in another quarterback for the next NFL season. While everyone is clamoring for Indianapolis to sign one of the marquee names in free agency at quarterback, they need to focus on re-signing Anthony Castonzo.

When the 2019 season concluded, Castonzo expressed that he would consider his future in the NFL. However, last month, the veteran left tackle announced that he would be returning for his 10th season.

Regardless of who is under center for the Colts in 2020, bringing back Castonzo should be the NFL team's No. 1 priority. Considering Indianapolis' current cap situation, they have plenty of money to get a deal done.

Jacksonville Jaguars — De'Vondre Campbell

Last offseason, the Jaguars were taken aback when Telvin Smith announced that he would be stepping away from the NFL. From 2014-2018, Smith amassed 587 tackles and nine interceptions with Jacksonville.

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While Smith remains away with the team, Myles Jack continues to man the middle of the defense. With that being said, the Jaguars need to find a viable replacement for Smith.

Instead of trying to draft his replacement, Jacksonville should try to sign De'Vondre Campbell on the open market. This past NFL season, Campbell had the best year of his career, recording 129 tackles and two interceptions with the Atlanta Falcons. Also, it's important to note that Campbell has played in a similar defense with the Falcons.

Tennessee Titans — Ryan Tannehill

The million-dollar NFL question (or questions) for the Titans is whether they should retain Tannehill or Henry. Another scenario that could come to fruition is Tennessee being able to re-sign both of them for the foreseeable future.

But if the NFL team has to make a decision, paying Tannehill might be the wiser move. In recent seasons, some teams have paid their running backs and have immediately had buyer's remorse.

Following a season where he rushed for a career-high 1,540 yards and 16 touchdowns, Henry could be asking for a deal that makes him the highest-paid running back in the NFL. In that case, the Titans should draft his replacement and retain Tannehill under center. Of course, the ideal resolution for Tennessee would be preventing both of them from entering free agency.