INDIANAPOLIS, Ind. – It was a year ago, to the day, when Clayton Geathers’ world was rocked by one of his signature hits.

It was Nov. 20, 2016 and the Colts were clinging to a 24-17 lead over Tennessee at Lucas Oil Stadium. It was late, but the Titans were driving. With 2:45 remaining, they faced a fourth-and-2 at the Colts’ 19-yard line. The Titans put the game in the hands of power back DeMarco Murray, who headed left and looked for the slightest crease.

He found Geathers, who squared up and stuffed Murray, who would finish as the NFL’s third-leading rusher, for no gain.

“I remember the play,’’ the Indianapolis Colts’ veteran safety said Monday. “It was a good play.

“Things happen, but they happen for a reason.’’

Whatever that reason, Geathers has come full circle.

The jarring hit on Murray was his final of the season. His next hit is expected Sunday. At Lucas Oil Stadium. Against the Tennessee Titans, perhaps even Murray.

Geathers considered the synchronicity of it all, and smiled.

“Yeah, I laugh sometimes,’’ he said. “It’s just the way He works. It’s been a year and if I play Sunday, it’s the game where it all happened last year.

“It’s kind of crazy how that happens.’’

Geathers suffered a concussion when stonewalling Murray and shortly thereafter was diagnosed with a neck injury that would force him to miss the final six games of the season. He underwent surgery in March to repair a bulging disc in his neck.

The long rehab process, which included spending the first 10 weeks of the season on the physically unable to perform list, ended last week when the Colts added him to the active roster.

The final step: returning to the playing field.

Geathers has been practicing for two weeks, gradually reacquainting himself with the rigors of the position and his teammates, and testing the stability of his neck as much as possible in a controlled practice environment.

What tells him he’s ready?

“Going through the journey, going through everything, checking off all the boxes,’’ he said. “And I’ve had no setbacks. I haven’t had any setbacks. That’s why I feel like I’m ready.’’

There’s only one remaining box that requires a checkmark.

“Pretty much it’s the game,’’ Geathers said.

Well, there will be one other box that warrants attention: that first hit. Geathers has been the back-end enforcer for the defense.

“We call him the ‘muscle,’’’ cornerback Rashaan Melvin said. “He’s the muscle of our defense and the muscle of the secondary. The guy can do a lot of good things – come down in the box and completely annihilate running backs.

“He plays with an edge. He plays with an attitude and it shows.’’

Geathers conceded a bit of anxiety will remain until he delivers a blow against the Titans.

“You’re human. You have thoughts,’’ he said. “But everything leading up to now has been good. I’m confident in (his neck).

“Whenever I get the first hit it’s going to be emotional. Just padding up is going to be emotional for me. Whenever that comes, it’s going to be something.’’

Chuck Pagano insisted his third-year safety hasn’t missed a beat while working his way back.

Geathers has “attended every meeting and been involved in everything other than practice,’’ he said. “He’s been like another coach, another set of eyes.

“Physically he’s in great shape. Moving around really well. He’s lighter than he’s ever been.’’

Geathers is listed at 220 pounds, but admitted he’s dropped about 5 pounds.

At least initially, the Colts will have Geathers on a pitch count.

“It would be stupid of us to throw him in there and say, ‘You’re going to play 50, 60 snaps,’’ Pagano said.

Last season, Geathers missed the opener against Detroit with a foot injury. He returned and started week 2 at Denver, and was supposed to be on a pitch count. He eventually played 34 defensive snaps – he finished with five tackles – before soreness in his foot made him pull himself from the game.

“We’re going to be on a pitch count,’’ Geathers conceded. “Whatever the number is, the number is. We pretty much go from there.’’

He added the defense has gotten better over the past month, and “I’m just trying to add to that. That’s always been my mindset, just adding to that, doing my job and contribute any way I can.’’

It’s important for Geathers to prove over the final six games he can be a critical component in a retooled defense. The 2015 fourth-round draft pick would give the Colts serious depth at safety moving forward, joining injured rookie Malik Hooker and Matthias Farley.

More medical matters

Quarterback Jacoby Brissett and cornerback Kenny Moore II remain in the NFL’s concussion protocol. Pagano expects Brissett to be cleared and start against the Titans.

The Colts also anticipate the return of starting strong-side linebacker John Simon, who’s missed the last three games with a stinger. Defensive lineman Hasaan Ridgeway is “week-to-week,’’ according to Pagano with a shoulder injury, which means he’ll probably miss multiple games. Tight end Darrell Daniels is day-to-day with a hamstring injury.

Also, tight end Erik Swoope is close to being moved from the injured reserve list to the active roster. He has been rehabbing following knee surgery during the preseason.

Swoope said he’s “foaming at the mouth’’ in anticipation of seeing his first action of the season.

“This bye week,’’ he added, “I stayed around and I worked out throughout the course of the week, just trying to get my bearings back.

“I’m just slowly counting down, but I’m ready to go.’’