Houston Texans general manager Rick Smith and second-year head coach Bill O’Brien are in the enviable position of building around the NFL’s best all-round defender in defensive end J.J. Watt. But in the same vein, both Smith and O’Brien may find that task difficult over the next two years.

The superstar machine who’s collected 51.5 sacks and two Defensive Player of the Year awards the last three seasons nearly carried the Texans into the postseason last year with a 9-7 record, but fell just short in the AFC Wild Card race.

Houston has limited options when free agency starts next month, and could face a major exodus on both sides of the ball in 2016. The Texans have $132 million devoted to player salaries next season, leaving them with $10.9 million in cap space to retain current players and possibly adding some coveted free agents.

And they don’t have a franchise quarterback clogging up most of their cap, a fact Smith and O’Brien could address in May’s NFL Draft with the No. 16 overall pick, and six more in the later rounds.

Essentially, Smith and O’Brien will have to make some difficult choices with the current roster. They’ll have to decide if their young emerging talent in the secondary is ready to take on a larger role, and if last season’s No. 1 pick Jadeveon Clowney is ready and healthy enough to form a dynamic, seemingly unstoppable pass rushing tag team with Watt.

Otherwise, the Texans will be forced to cut ties with several players in order to make the requisite cap room for some of their veterans.

Smith’s short term goal will have to revolve around a number of defensive players hitting the open market on March 7, the first official day of free agency. Houston can of course negotiate with their players now, but offers from other teams will start rolling in after contracts officially expire in the afternoon of March 10.

Next month major contributors in the Texans secondary and linebacker corps are up for new deals. There’s veteran cornerback Kareem Jackson, and free safeties Kendrick Lewis and Danieal Manning, as well as linebackers Brooks Reed and Akeem Dent.

Defensive tackle Ryan Pickett, who was signed after rookie Louis Nix III was placed on injured reserve in September and typically lined up next to Watt will also be a free agent, as will Watt’s immediate back-up on the depth chart Tim Jamison. Pickett’s back-up Jerrell Powe is also scheduled for a new contract.

On offense, only right tackle Derek Newton and backup quarterbacks Ryan Mallett and Case Keenum are free agents next month, but in 2016 Houston’s offensive line could be raided by opposing front offices. Despite the Texans issues in passing game, the offensive line allowed only 26 sacks last season, No. 4 in the NFL, and helped Arian Foster spearhead the league's No. 5 rushing attack.

A total of 16 players will be unrestricted free agents in 2016, nine of which are on offense, and five on the offensive line like starting center Chris Meyers, right tackle Tyson Clabo, third-string left tackle Will Yeatman, and starting guards Brandon Brooks and Ben Jones. Last year, Houston used its second-round pick on offensive lineman Xavier Su’a-Filo, but he will need help if either Brooks or Jones bolts.

Beginning on the defensive side, the Texans do have some youth in the secondary that could force them to pause before retaining Jackson, Lewis or Manning, a solid group that ranked only No. 21 in the league last year and gave up 28 touchdowns, tied for the ninth-worst mark.

For starters, there’s safety D.J. Swearinger, 23, who was third on the team with 74 tackles, along with six passes defended, three forced fumbles and two interceptions. O’Brien also received a huge boost from cornerback A.J. Bouye, 23, in his second season, ranking second on the team with 10 passes defended and three interceptions. Cornerback Jumal Rolle, 24, was tied with Bouye with three picks in only 10 games during his rookie year.

Other than their youth, Swearinger, Bouye and Rolle are currently on cheap deals. Together the trio will represent a shade over $2 million of the Texans cap, less than half of Jackson’s hit for 2014. That group can also turn to 30-year-old cornerback Johnathan Joseph for guidance before his deal runs out after next season.

As for defensive tackle, Nix figures to return from the arthroscopic knee surgery that kept him out most of last season, and Powe and Jamison are unlikely to command very expensive deals.

Linebacker could be tricky, but the return, or really full debut, of Clowney will allow O’Brien flexibility in his defensive schemes.

The Texans are then likely to address the issues at quarterback, offensive line and possibly wide receiver in the draft. Unless they trade up, Houston is highly unlikely to snag the two highly touted quarterback prospects, Florida State’s Jameis Winston and Oregon’s Marcus Mariota, at No. 16 in the first round.

But tackles like Iowa’s Brandon Scherff, Stanford’s Andrus Peat, and LSU’s La’el Collins figure to be available when Houston is on the clock in the first round.

Though the NFL Combine could change things, CBS Sports has UCLA quarterback Brett Hundley projected as a second-round selection, a likely spot for Houston to address its most glaring need on offense.

Pairing Hundley with a young receiver could also be an option, and it could allow Houston to release veteran Andre Johnson, who has a costly $16.1 million cap hit this season and a $14.6 million hit in 2016.

With DeAndre Hopkins notching 1,200 yards and six touchdowns last season, he could be teamed up with first-round talents like Oklahoma’s Dorial Green-Beckham or first to second round prospects like Auburn’s Sammie Coates or Ohio State’s Devin Smith.