HOUSTON -- In the four years Bill O'Brien has been the coach of the Houston Texans, he has focused on building a "big, strong, physical team."

It's easy to see by looking at the roster. Houston has built a team with a number of athletic, physical specimens, such as DeAndre Hopkins at receiver, Jadeveon Clowney at outside linebacker and J.J. Watt at defensive end.

"You have to have a philosophy of what you want your team to look like and you have to stick by that," O'Brien said. "That's just our philosophy. It's something that [general manager] Brian [Gaine] and I really believe in. And if you start making exceptions then you have a team full of exceptions. And that's not what you're looking for. At certain positions, maybe we will make an exception, but not very often because I think it's important to have, like I've said since the day I arrived here, a big, strong, physical team. And that's what we're trying to do."

Gaine continued to give O'Brien that physical roster this offseason, adding players such as safety Tyrann Mathieu, cornerback Aaron Colvin and 6-foot-7, 330-pound offensive lineman Seantrel Henderson in free agency. Several times, when Gaine was asked about players he signed, he led with the fact he liked a player's build, or his "height, weight and speed."

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"In terms of prototypes, we break it down by position in terms of the height, weight, speed and physical parameters that we might be looking for," Gaine said. "Equally, specific skill sets that we may be looking for at variating positions, whatever they may be."

O'Brien said the Texans have specific parameters at every position that they don't like to stray from. For example, at outside linebacker they look for "guys that have good length, have good pass-rush ability. Athletic guys, smart guys. Guys that can set the edge but can also rush the passer."

This philosophy was particularly evident in Gaine's first draft as the Texans' general manager. When asked about the team's top pick, Justin Reid, Gaine first pointed out the safety has "the prototypical body type" for the position.

On paper, the physical characteristics of the Texans' 2018 draft class stand out. Along with Reid, the Texans drafted outside linebacker Duke Ejiofor (6-foot-4, 275 pounds) and tight end Jordan Thomas (6-foot-5, 280 pounds). Even slot receiver Keke Coutee, who says he is 5-foot-9, has a good build for the position, according to O'Brien.

Though it's easy to draft players who fit the build Gaine and O'Brien are looking for, the Texans' coaching staff still has work to do.

"We really pride ourselves on our ability to develop players," O'Brien said. "I think we've proven over the years, here and other places, that we can develop young players into professional players."

One example of those players is cornerback A.J. Bouye, who arrived in Houston in 2013 as an undrafted free agent. When O'Brien and his coaching staff took over in 2014, Bouye continually improved and was the Texans' top corner -- and one of the best in the NFL -- in 2016. He signed a five-year, $67.5 million contract in 2017 with the Jacksonville Jaguars.

Given all the additions, the Texans have achieved their goal with the players they've signed this offseason, and hope to develop them into productive contributors in 2018.

"I've put that emphasis on height, weight, speed, improving our physical parameters -- bigger, longer, stronger, adding more speed and athleticism to the team," Gaine said after the draft. "We feel like we were able to do that [during the draft] at the positions that we selected."