HOUSTON -- Despite scoring more than 30 points in five of Deshaun Watson’s six starts last season, the Houston Texans went 3-3 in those games, in part because the defense couldn't maintain a late lead.

While the Texans dealt with injuries on their defensive front seven in 2017 -- most notably to defensive end J.J. Watt and outside linebacker Whitney Mercilus -- that part of the defense should return to form in 2018. Houston also saw two rookie linebackers -- Zach Cunningham and Dylan Cole -- rise to prominent roles alongside Benardrick McKinney.

Kevin Johnson and the Texans secondary struggled in 2017. AP Photo/David J. Phillip

But the secondary has question marks galore. The Texans were unable to hold a lead against Tom Brady or Russell Wilson on late-game drives in losses last season. And in their third loss with Watson as a starter, the Texans allowed 42 points at home to the Chiefs and Alex Smith threw for 327 yards and three touchdowns.

The Texans’ highest-rated cornerback from a year ago, Johnathan Joseph, is a free agent, but he said he would like to return to Houston. Joseph, who will be 34 at the start of next season, has proven steady for the Texans, but not as a shutdown corner. The Texans also have Kareem Jackson and Kevin Johnson, who is coming off a season to forget. Johnson, the Texans’ first-round pick in 2015, has dealt with injuries each of his past two seasons and struggled when healthy. In 2017, Johnson was ranked 121 out of 121 eligible cornerbacks by Pro Football Focus.

Houston has nearly $64 million of available salary-cap space this offseason and should use some of it on an established cornerback. A year ago they lost A.J. Bouye to the division-rival Jacksonville Jaguars during free agency, which proved to be a huge difference for both teams' secondaries. In 2016 with Bouye as their top corner, the Texans allowed the second-fewest passing yards per game; last season they ranked 24th in that category. The Texans do also have 2017 fifth-round pick Treston Decoud, who could see more playing time in his second season.

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There are a few top corner options available during free agency, including Malcolm Butler, Kyle Fuller and Trumaine Johnson. Butler’s best season came in 2016 when he had 63 combined tackles, four interceptions and 17 passes defended. He is well known for intercepting Russell Wilson at the goal line to seal a New England Patriots win in Super Bowl XLIX.

Fuller missed all of 2016 but had a good bounce-back season for the Chicago Bears, ranking as PFF’s No. 21 cornerback. According to PFF, Fuller allowed the 17th-lowest completion percentage, 51.3 percent, and led the NFL with 17 pass breakups in 2017.

Johnson has played the past two seasons with the Rams under the franchise tag and saw his completion percentage against go down to 57.3 in 2017.

The Texans also didn't get much playmaking from their safeties in 2017. Lamarcus Joyner and Tyvon Branch are the top two available free agents, along with other experienced players like Tre Boston, Eric Reid, Morgan Burnett and Corey Graham, who is coming off a Super Bowl victory with the Eagles. Without a pick in the first two rounds of the draft, Houston could take a safety like Jordan Whitehead from Pitt or DeShon Elliott from Texas if either is available in the third round.

The Texans are in a unique position with Watson and an elite receiver in DeAndre Hopkins to lead their offense, but they need to make sure that when they put up a lot of points they have a secondary that can hold those leads against capable quarterbacks. Last year Watson put them in a position to beat the Patriots and Seahawks on the road, in wins that could have reshaped Houston's season, but the defense couldn’t get a stop, which is something the Texans can’t afford to let happen again if they want to return to the playoffs in 2018.