Rather than hire an offensive coordinator to replace George Godsey, O'Brien will instead call the plays himself and operate as his own offensive coordinator while shifting receivers coach Sean Ryan to quarterbacks coach.
It was all part of a sweeping batch of changes orchestrated by O'Brien involving the AFC South champions' coaching staff, moves intended to bolster the Texans' chances of becoming a more dangerous playoff contender next season.
Not only did O'Brien opt to have himself run the offense, he maintained continuity and acumen on the defensive coaching staff. O'Brien promoted veteran defensive coordinator Romeo Crennel to assistant head coach-defense and named linebackers coach Mike Vrabel as the Texans' new defensive coordinator.
O'Brien calling the plays and taking over offensive coordinator duties rather than hiring another coach to run the offense wasn't a surprise. It was a move anticipated in league circles ever since the Texans parted ways with Godsey on Monday two days after $72 million quarterback Brock Osweiler threw three interceptions during an AFC divisional-round loss to the New England Patriots.
O'Brien didn't really have an in-house alternative as a play-caller or an outside hire that made sense. The Texans had a historically bad offense. They scored 25 touchdowns, 23 of them on offense. It was the lowest output for a playoff team in a non-strike season since the NFL expanded its season to 16 games in 1978.
No one would have been as well-versed in the complicated system O'Brien brought with him from his days as the Patriots' offensive coordinator while collaborating with star quarterback Tom Brady.
O'Brien has the most extensive knowledge and background in the system and has an aggressive philosophy.
O'Brien was already calling the plays periodically throughout the season after taking over play-calling duties from Godsey following a 27-0 shutout loss to the Patriots in the third game of the season. O'Brien and Godsey later collaborated on the play-calling, standing side by side on the sideline holding play sheets.
With two years remaining on a five-year contract, O'Brien is betting on himself and essentially pushing the chips into the middle of the table by operating as his own de facto offensive coordinator regardless of job titles.
The Texans finished 29th in total offense and 31st in red-zone offense last season, struggling to consistently move the football or score points. It's unlikely to think the offense would regress more with O'Brien having a full season at the controls.
The Texans ranked 28th in scoring, tying them with the 3-13 Chicago Bears.
It makes sense to think that O'Brien inserting himself might provide an upgrade to a moribund attack that struggled mightily last season as Osweiler threw 16 interceptions during the regular season with just 15 touchdown passes.
Could the Texans use some more creative ideas offensively? Absolutely, but their greatest problem is solving a quarterback quandary that's obviously holding back a division champion that's otherwise built to be an annual playoff contender.
At least the defense remains in strong hands.
Crennel's contract, which previously paid him $1.8 million as the highest-paid defensive coordinator in the game, was expiring. He's believed to have received a raise after coaching the Texans to the top defensive ranking in the NFL despite missing star defensive end J.J. Watt due to a back injury that required surgery.
"He always emphasizes bringing the juice," Texans defensive end Christian Covington said of Crennel, who has earned five Super Bowl rings. "To have a man like him coaching us, his raw passion for the game is basically displayed every game. His love for the game is unmatched.
"He's a guru. He's able to switch up different base packages to make it easier on the defense. He's really looking at it from the outside in, that's just the type of coach he is. Just like players face obstacles, coaches face obstacles. He's the kind of man who knows how to get the most out of people."
A former Super Bowl-winning assistant coach with the Patriots and Giants, Crennel provides tough love when he feels it's needed, blending stern words with encouragement. Crennel has vast experience, having previously been a head coach for the Cleveland Browns and Kansas City Chiefs.
"I think it's a combination," Crennel said. "I mean, sometimes you have to try to give them a little rah-rah speech. Other times, you have to yell at them. But basically, you have to present them a good plan that you think will work. Then, they have to buy into that plan and execute it on game day."
As for Vrabel, he was in heavy demand and the Texans retained one of the rising stars in the NFL coaching industry.
The former New England Patriots All-Pro outside linebacker turned down the San Francisco 49ers' defensive coordinator offer last year, receiving a raise and additional responsibilities in the process. He was scheduled to interview for the Los Angeles Rams' head coaching job that went to Sean McVay as the replacement for Jeff Fisher.
Both Washington and the San Diego Chargers wanted Vrabel for their defensive coordinator vacancies.
Vrabel was praised by Patriots head coach Bill Belichick prior to the Texans' AFC divisional-round playoff loss at Gillette Stadium.
"Mike does a tremendous job," Belichick said. "As a player he was very astute, had a great understanding of his position and technique and how to play his spot and corresponding positions from an overall standpoint. He had a very good grasp of the overall defensive and offensive concepts and how they would attack different fronts. We talked about that.
"Of course never worked with Mike as a coach. As a player, he certainly showed those qualities. A lot of players understand the game well and have a good awareness, but Mike has good leadership, good communication. He's direct. He gets along with everybody, has a good way of working with people, got good leadership skills. Those things are very important."
Vrabel is regarded as a tough, passionate coach who relates well to his players. The former Patriots standout has a demanding style, but he also communicates well. He's been instrumental in the development of Pro Bowl defensive end Jadeveon Clowney along with outside linebackers Whitney Mercilus and John Simon and inside linebacker Benardrick McKinney with veteran Brian Cushing remaining productive under his coaching tenure.
O'Brien made it a point to emphasize Vrabel's skill as a coach during the playoffs.
"He definitely has a great way of communicating things that he probably saw as a player, ways that he prepared as a player," O'Brien said. "Obviously, he communicates how he wants those guys to play, teaches the defense, teaches the front. He's involved with a lot of different areas of the defense - the coverage, the rush, stopping the run, and he does a great job.
"I'm sure that the fact that he played 14 years, many of those experiences help him teach too. The players, they obviously have a ton of respect for that, his playing career. Most importantly, they have a lot of respect for him as a coach, how he teaches, and how he communicates."
Learning from Vrabel how to trust his keys and react faster to the football, McKinney led the Texans with 129 tackles to go along with five sacks in his second NFL season. A second-round draft pick from Mississippi State, McKinney was the lone NFL player this season to record at least 100 tackles and five sacks.
"Coach Vrabel has done an unbelievable job of teaching me where to be, in the right spot," McKinney said. "He's an unbelievable coach. He loves the game of football. He tells us how much he loves coaching us. He's a great guy and a great coach."
University of Texas head coach Tom Herman, the former University of Houston head coach who initially clashed with Vrabel as fellow Ohio State assistant coaches working for Urban Meyer, heavily praised his friend and predicted big things ahead in his coaching future last summer.
"The sky's the limit for Mike, he's a natural," Herman said. "We're watching the career of a head coach in the NFL unfold right before our eyes."