KC Chiefs safety Tyrann Mathieu returned to practice Thursday. Here’s why that’s huge

Defensive coordinator Steve Spagnuolo and others on the Chiefs’ coaching staff were taken “a little bit by surprise” when safety Tyrann Mathieu got hurt in the first quarter of last weekend’s AFC Divisional Round win over the Buffalo Bills.

Losing the three-time All-Pro, who had to exit the game in accordance with the NFL’s concussion protocols after taking a teammate’s knee to the helmet, left the defense without an integral leader.

It also threw a wrench into the Chiefs’ very game plan.

“We did have a package (for him),” Spagnuolo said. We were going to do something a little bit different. Then we had to throw the thing completely out that we had especially for Buffalo. So that set us back a little bit.”

Though the Chiefs escaped with a 42-36 overtime win, the defense gave up several explosive plays as it struggled to contain Bills wide receiver Gabriel Davis — he finished with 201 yards and four touchdowns.

But there’s reason for optimism as the Chiefs prepare to face a dynamic Bengals offense in the AFC Championship Game at Arrowhead Stadium this Sunday: Mathieu participated in practice on Thursday.

“I thought he did a nice job, moved around well,” Chiefs coach Andy Reid said afterward. “He was fine today, so he just has to go through the rest of the protocol here and finish that up, and make sure he’s OK as he goes through it.”

He’s not in the clear just yet — Reid said Mathieu would be getting another test after practice as he continues through the league protocol — but having his presence on the field Sunday is looking more likely. And that makes a huge difference for the Chiefs.

Though cornerback L’Jarius Sneed and others said the Chiefs relied on a “next man up mentality” with Mathieu out, there’s no denying how much of an impact he makes on the field.

“Anytime you lose a player of Tyrann’s caliber, your team is going to be affected,” defensive end Frank Clark said. “He leads in so many different ways on and off the field, just through his presence alone.”

There’s of course the 76 combined tackles, three interceptions, three fumble recoveries and six pass deflections he’s racked up this season, but perhaps just as important — if not more — is Mathieu’s leadership in steering the mindset and direction of the defense.

Take the moment right before a play starts, for instance.

“Every snap, he warns me and tells me what’s coming and what to expect and all of that,” Sneed said. “Every snap he does it.”

If the defense starts to get off-track during a game, Mathieu is often the teammate whom players turn to. Clark noticed the difference without him against the Bills.

“You’ve seen at times during the game where we kind of struggled,” Clark said. “Whether it’s with pass rushing, getting the stops when we needed them ... we also gave up a few passes in the back end.

“Those are things that, when Tyrann is there, he’s able to help with the adjustments and help calm situations down … where it may seem like things are getting overhyped or things like that.”

If all goes according to plan with Mathieu’s progression through the concussion protocol, he’s poised to be a huge help on Sunday with a third straight trip to the Super Bowl on the line.