The Texans fired David Culley on Thursday, a move that came four days after Houston wrapped a 4-13 campaign in his first season as head coach.

“I came to this difficult but necessary decision after reviewing our football operation,” Texans general manager Nick Caserio said in a statement released by the team.

“While a change after one season is unusual, we had philosophical differences over the long-term direction and vision for our program moving forward. 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.”

Culley told Houston media outlets SportsTalk 790 and KRIV-TV that he had three years left on his contract and that his salary is guaranteed.

“I loved every minute of being the head coach of the Houston Texans. I appreciate the players and coaches for staying the course with me through the ups and downs of our season,” Culley said in a statement released by the team.