The Houston Texans will be taking on a familiar face when they play the Kansas City Chiefs in the AFC divisional playoffs Sunday at 2:05 p.m. CT at Arrowhead Stadium.

A really familiar face.

All-Pro safety Tyrann Mathieu used to be a part of the Texans’ secondary in 2018. After signing a three-year, $42 million contract with the Chiefs, Mathieu produced 75 tackles, 2.0 sacks, four interceptions, and 12 pass breakups in 16 starts for Kansas City.

“He’s a big part of it,” O’Brien told reporters Monday. “He’s playing really well. Line him up in different spots, plays nickel, plays safety. They do a good job. They mix it up on you, they spin the dial from one snap to the next, you really don’t know what you’re going to get. So, you’re going to have to be very, very alert, you’re going to have to have a great week of communication.”

In the wild-card round against the Buffalo Bills, part of what helped the Texans prevail 22-19 in overtime was quarterback Deshaun Watson being careful with the football. The two-time Pro Bowl signal caller went 20-of-25 for 247 yards and a touchdown, though he did take seven sacks on the afternoon.

“You’re going to have to have a great week of preparation, because (Steve) Spagnuolo does a great job,” O’Brien said.

Mathieu is a known quantity for the Texans as he spent the 2018 season with the Texans after playing the first five seasons of his career with the Arizona Cardinals. While he didn’t get to stay in Houston, Mathieu used the “prove-it” aspect of his one-year contract with the AFC South club to audition for suitors who would be willing to pay retail for Mathieu’s services.

In the Week 6 encounter between Houston and Kansas City, Mathieu had 10 tackles and a pass deflection in 89 snaps. If the “Honey Badger” can add more production, it could help the Chiefs defend their home-field advantage in the rematch.