HOUSTON -- Throughout the week, members of the Houston Texans defense can often be found in Romeo Crennel's office.

His open-door policy, veteran cornerback Johnathan Joseph said, is one thing that sets the defensive coordinator apart from others in the same position.

"We've got a great relationship," Joseph said. "We talk a lot. But we don't really talk about football as much. We talk about everything but football sometimes. ... Just family, kids, some of the younger guys on the team. Just the business of the NFL.

"A lot of the time, some of those guys, they're busy and they don't have as much time to talk with guys and stuff like that. His door is always open."

Crennel, who was Houston's defensive coordinator from 2014-16, was named assistant head coach in 2017 after head coach Bill O'Brien promoted Mike Vrabel to defensive coordinator. After Vrabel was named the Titans head coach this offseason, Crennel stepped back into his old role.

Under Crennel in 2016, the Texans had the No. 1 defense in the NFL, allowing an average of just 301.3 yards per game. Last season, Houston fell to 20th in that category.

This spring, O'Brien said that with Crennel taking over again on defense, he thinks the unit will have the same foundation, but the 71-year-old Crennel will "add his own little spin to it."

"It's just things that he does, his style is a little bit different," O'Brien said. "That's something that the players have bought into."

For most players, it's the way Crennel coaches that is different from when Vrabel was in charge.

"I think Vrabel has more energy," Joseph said. "He's out there running around with us on the field and having fun. He's definitely in guys' faces a little more. I think Romeo's more laid-back, more reserved, more of a teacher. He's not really a yeller or a hollerer.

"I think he demands the respect of everyone in the room. And he gets that. But I think their approach to it is a little different."

That ability to command respect without yelling is something Crennel has learned as he's been in the league.

"I'm as competitive as Mike Vrabel, [but] I'm not as loud," Crennel said. "I used to be loud like that, but as I've grown a little bit older, I don't have to yell as much."

Crennel said he has always tried to get to know his players on a level other than just football, and that he tries to coach each player based on how each individual is motivated.

"Some guys you have to yell at. Some guys you can talk softly to. Some guys you have to give them [a] push. Some guys you put your arm around," Crennel said. "So, you have to figure out what method works best for each player."

Added Joseph: "He has a different way of getting to you. He wants to win, just no different than the other guy. But he's not one of those rah-rah guys. But if you keep messing up, he'll definitely let you know. I think that's the way it should be."

But at the end of the day, Crennel's goal is simple: get this defense back to playing at the high level it was two years ago. Safety Tyrann Mathieu, who is just one of the many talented playmakers the Texans have on defense, said he thinks that is possible with this group.

"I've played with some great defenses, some top-five defenses, [and] I feel like this team has the same capabilities," Mathieu said. "I could go up and down the list just naming a bunch of guys that can do a lot of good things.

"For us, it's going to just come down to having some effort, having some swagger, even though things may not have gone well last year, but still coming out this season with a lot of energy, a lot of swagger, as if we made the playoffs."