My football career ended with a concussion. I was 17.

For the next 30-plus years, I didn’t give much thought to long-term repercussions. But with the NFL now at a point where dazed players are immediately removed from a game, not to come back, I reflect back on my own brain trauma — and I was way more than dazed — and wonder if it will matter some day. Or if it already does.

It was the last game of my senior year at Los Angeles Lutheran High School.

I was the second guy from the right of the forward five guys on the kick-return team. The coaches had warned us that Pater Noster never kicked deep; they always kicked the ball onside, hoping to recover it or get some decent yardage out of it as it bounded into the receiving team’s formation.

We were at Cal State Los Angeles, Pater Noster’s home field. My bigger concern that night November night was the size of our opponents’ interior defensive linemen. Both of them weighed 240 pounds, which was enormous in high school football back then. (I was maybe 180 pounds.) As the starting offensive right tackle, I was going to have to deal with those big guys.

But the opening kickoff had my attention. I remembered the coaches’ warning, and the game opened with Pater Noster kicking the ball straight at me.

My theory is they saw my number (63) and decided I was a clumsy lineman, but I played third base for the baseball team, and I fielded the bouncing ball, no problem. It was after it was in my hands that the trouble began.

I had gone to my knees to handle the ball. No problem. Except the ball was, by high school and college football rules, dead. This was not the NFL, where the play continues until a player is down by contact.

For some reason, though, I thought I could advance the ball — because I began to get up to move the ball forward a few yards before I was tackled.

Meanwhile, the big kid to my right, a junior defensive end named Wayne  Wilson, had come over to help. He decided to get in front of me, maybe throw a block, but he leaped over me just as I was rising.

(This was told to me weeks later by those who had seen the film.)

The toe of Wilson’s shoe hit the lower back of my helmet, causing whiplash, and I was out like a light. Never knew what hit me. Out cold. And for more than a few moments.

I was unconscious long enough that my father was able to see me motionless on the turf … come out of the stands on the other side of the field … walk around to my team’s bench … and be nearby when I finally came around, perhaps after something of a seizure. (No one ever quite told me.) And I regained consciousness only with the aid of smelling salts.

My first post-KO memory is of the lights creating a halo around the head of our team’s lovable coach, Jim Young, who was bent over me and cheerfully said, “Gosh, Obe, I thought you were dead!” It was meant to cheer me up.

Back then, being knocked out was something of a badge of honor. But I always wondered if something scary had happened while I was out, which is why my coach said what he said.

My badge of honor, however, came with a night of “check on him every few hours to make sure he’s not, you know, in a coma.”

I was never going to play again that night. I was woozy. This was an era when concussed players went back in, if you could … but I was in a fog.

The home team sent for an ambulance, as I sat on the bench trying to gather my wits. Before it arrived, however, our starting fullback, Ken Meier, suffered a serious injury, and they stuck him in the ambulance, instead.

I remember seeing our quarterback, Dennis Doescher, throw a couple of long touchdown passes (I remember the ball in the air), and we won 28-20 to gain a share of second place in the Olympic League.

After, my parents took me to Community Hospital in Long Beach, and I got X-rays. My head hurt, but the medical people saw no sign of bleeding, so I went home.

It was not over, however. I had headaches for weeks, and for at least two months, whenever I stood up, especially from a lying position, I had head-rushes so intense that they were rather like blackouts — everything going dark before my head cleared and the lights came back on.

I assume that made it a fairly severe concussion. The duration of problems.

Will it matter? Maybe we will find out, as we go.

I do know this: I cannot imagine athletes suffering multiple concussions of that sort and going back out on a football field. Not for months. Maybe not ever.

And that is the NFL’s problem. Concussions are far more serious than regaining your equilibrium and getting back out there. I know that from personal experience.