“Earlier today, I met with David Culley and Tim Kelly to inform them we will be moving in a different direction at the head coach and offensive coordinator positions,” Texans general manager Nick Caserio said. “I came to this difficult but necessary decision after reviewing our football operation. While a change after one season is unusual, we had philosophical differences over the long-term direction and vision for our program moving forward.”Culley is the second Black head coach to be fired this week, after the Miami Dolphins relieved Brian Flores of his duties. That leaves Pittsburgh’s Mike Tomlin as the only remaining Black head coach, along with two others of color — the New York Jets’ Robert Saleh and Washington’s Ron Rivera, according to The Institute for Diversity and Ethics in Sport at the University of Central Florida.That, in a 32-team league where a majority of players are of color, focuses attention on the NFL’s six current head coaching vacancies, given the league for years has been under public pressure to increase diversity in its leadership positions. NFL commissioner Roger Goodell himself criticized last year’s round of hirings, when two minority coaches, Culley and Saleh, were hired out of seven openings. Goodell said last year that’s “not what we expect going forward.””We want to make our NFL clubs diverse,” Goodell said in February. “Head coach is important. We had two minority coaches hired, but it wasn’t what we expected.”Culley’s firing also comes two days after another top NFL official — executive vice president of football operations Troy Vincent — told the Washington Post he saw a double standard when it came to NFL or collegiate teams firing Black coaches after short tenures or winning seasons.Vincent, who is Black, mentioned Tony Dungy, whom the Buccaneers fired after the 2001 season with a 54-42 regular-season record over six seasons, including winning seasons in his final three years. He also referred to Jim Caldwell, whom the Lions let go let go just after the 2017 regular season after three winning seasons in four years — for a club that had only one winning campaign in the prior 13 years.Vincent also mentioned Steve Wilks, whom the Cardinals fired a few years ago after just one season, albeit with a 3-13 record.”There is a double standard,” Vincent told the Post. “I don’t think that that is something that we should shy away from. But that is all part of some of the things that we need to fix in the system. “We want to hold everyone to why does one, let’s say, get the benefit of the doubt to be able to build or take bumps and bruises in this process of getting a franchise turned around when others are not afforded that latitude? … We see it at the collegiate level. And we’ve seen that in history at the (professional) level.”Besides the Texans and Dolphins, the teams with current head coaching vacancies are the Bears, Broncos, Giants and Vikings.The Rooney Rule aims to boost candidate diversityThe NFL has said it’s tried to increase diversity in its ranks of head coaches, after years of criticism. In 2003, the league adopted the Rooney Rule, requiring teams to interview at least one “diverse” candidate for head coaching vacancies. In 2009, the Rooney Rule was expanded to include general manager jobs and equivalent front office positions. The league in 2020 expanded the rule to require additional interviews. And late that year, the NFL passed a resolution that would reward teams with additional draft picks for developing minority coaches.Culley and Flores were two of five Black head coaches hired full-time in the last five years, according to the institute. The others were Anthony Lynn (Chargers, 2017-2020); Vance Joseph (Broncos, 2017-2018); and Wilks (Cardinals, 2018).Six others had been hired full-time since 2010: Hue Jackson (Raiders, 2011, and Browns, 2016-2018); Leslie Frazier (Vikings, 2011-2013); Romeo Crennell (Chiefs, 2012-2013, after coaching the Browns the decade prior); Lovie Smith (Buccaneers, 2014-2016, after coaching the Bears); Caldwell (Lions 2014-2017, after coaching the Colts); and Todd Bowles (Jets, 2015-2018).Of the league’s players this season, 58% were Black and nearly 10% identified with two or more races, while 25% were white, according to the institute.Culley says he ‘loved every minute’Culley, 66, was in his first head coaching job, having spent more than 27 years as an NFL assistant and 16 as a collegiate assistant. He was hired last year from the Baltimore Ravens, where he spent two years as an assistant head coach, passing game coordinator and wide receivers coach.Culley’s task at the Texans job looked like an uphill journey ever since he was hired. Watson had requested a trade from the team before Culley was hired, and star defensive lineman and pillar of the organization J.J. Watt was released just weeks after. Visit CNN Sports for more news, features, and videosBut despite the turmoil the team was in, Culley managed to rally his players and the Texans seemed to play above their station. “We appreciate Coach Culley for helping us navigate through a difficult season, but it is my responsibility to make decisions that I feel are best for our organization,” Caserio said. “The search for the next coach of the Houston Texans will begin immediately.” In a statement released announcing his firing, Culley said he “loved every minute” of being head coach of the Texans. “I appreciate the players and coaches for staying the course with me through the ups and downs of our season,” he said. “I’m disappointed we didn’t win more games and I won’t have a chance to improve on the lessons I’ve learned, but I fully understand this is a bottom-line business and I didn’t do enough. I want to thank the McNair Family and Nick Caserio for giving me this opportunity, I am forever grateful for the experience.”I wish this team and organization the best, they are building a special program and I truly believe the future is bright for Texans fans.”Culley is the sixth head coach to be fired after the conclusion of the 2021 season, after Flores was fired from the Dolphins, Mike Zimmer from the Minnesota Dolphins, Vic Fangio from the Denver Broncos, Joe Judge from the New York Giants and Matt Nagy from the Chicago Bears.CNN’s Leah Asmelash contributed to this report.