HOUSTON -- While the Houston Texans hope that a healthy Deshaun Watson will put them in the playoff race in 2018, there are other holes that need to be filled on a team that went 4-12 in 2017.

The Texans dealt with injuries to many key players last season, including Watson, defensive end J.J. Watt, outside linebacker Whitney Mercilus, running back D’Onta Foreman and tight ends C.J. Fiedorowicz and Ryan Griffin, but the team also failed to replace the production of players who left in free agency a year ago.

Here are three of the biggest needs the Texans have to address this offseason:

Offensive line: Three of the Texans’ starters on the offensive line in 2017 -- left tackle Chris Clark, right tackle Breno Giacomini and left guard Xavier Su’a-Filo -- are free agents. The unit struggled last season, though it did show improvement when blocking for the mobile Watson. The Texans could bring back Clark or Giacomini to compete for a starting tackle job, and right tackle Derek Newton also could return, as he is rehabbing from torn patellar tendons in both legs. By the time the season starts, Newton will have gone nearly a year and a half without playing in a game, but coach Bill O’Brien said the right tackle has been “working his tail off to get back and play.”

Center Nick Martin played well in his first season (he was hurt in 2016), but is rehabbing from an ankle injury for the second year in a row. Even if the Texans play Greg Mancz or David Quessenberry next season to fill in for Su’a-Filo, Houston needs to shore up the unit that protects Watson, its most valuable asset.

Secondary: The unit that was the second-best in 2016 took a nosedive this season, finishing the year ranked 24th in passing defense. The Texans were hopeful that 2015 first-round pick Kevin Johnson could replace the production that cornerback A.J. Bouye had in 2016, his final year in Houston. Instead, Johnson struggled and spent part of the season dealing with a sprained MCL. The Texans likely will bring back veteran cornerback Johnathan Joseph, but they need to figure out whether they think Johnson is capable or if they need to find someone else they can build their cornerback corps around. The Texans also lost safety Quintin Demps a year ago and could not replace his production in 2017.

Backup quarterback: Right now, the only two quarterbacks under contract are Watson and Taylor Heincke, who backed up veteran T.J. Yates in three games last season. The Texans saw just how important a backup quarterback is when they had rely on Tom Savage, Yates and Heincke after Watson tore his ACL in early November. The Texans are unlikely to re-sign Savage, but could choose to sign a veteran quarterback, perhaps bringing Ryan Fitzpatrick back. Houston could use a late pick in the draft to select and develop a young quarterback, but since they don’t currently have a pick until the third round, the team may choose to use those picks at other positions.