The Post Sports Live crew talks about Bryce Harper’s head-on collision with the outfield wall in Dodgers stadium during Monday night’s game. (Post Sports Live)

A vague memory drew me to my bookshelf to find a book published 50 years ago. I flipped pages, until I saw “The Rocky Road of Pistol Pete,” by W.C. Heinz in 1958 about Pete Reiser. Then I knew what I was seeking: a story to tell Bryce Harper before it’s too late to save him from himself.

At age 22 in 1941, Reiser finished second for National League MVP. In just 137 games, he had 70 extra-base hits and led the league in runs (117), batting (.343), doubles (39), triples (17), total bases, getting hit by pitches and, if they’d kept track of on-base plus slugging back then, that, too (.964).

He was as good in reality as Harper dreams of being.

Then Reiser started running into walls. He never led the league in anything again, except stolen bases a couple of times because he was harder to throw out than one of his later Dodger teammates, Jackie Robinson. In one season, Reiser stole home seven times.

“The Yankees think Mickey Mantle is something new. They forget Reiser,” wrote Heinz. “Maybe Pete Reiser was the purest ball player of all time. I don’t know. There is no exact way of measuring such a thing, but when a man of incomparable skills, with full knowledge of what he is doing, destroys those skills and puts his life on the line in the pursuit of his endeavor as no man in his game ever has, perhaps he is the truest of them all.”

After Heinz caught up with Reiser, then 39 and managing Kokomo in the Class D Midwest League, he wrote, “In two and a half years in the minors, three seasons of Army ball and 10 years in the majors, Reiser was carried off the field 11 times. Nine times he regained consciousness either in the clubhouse or in hospitals. . . . Seven times he crashed into outfield walls, five times ending up in an unconscious heap on the ground.. . . Three times Pete sneaked out of hospitals to play. Once, he went back into the lineup after doctors warned him that any blow to the head would kill him. . . . In the ’47 World Series, he stood on a broken ankle to pinch-hit.”

There were other injuries because, like Harper, Reiser did everything full bore. He ran wild on the bases, made every throw his hardest (he broke a bone in his elbow throwing) and got beaned, before helmets, several times.

Dodger GM Branch Rickey guaranteed Reiser’s entire ’48 salary if he would just sit out the entire season to heal. “That might have been the one mistake I made,” Reiser told Heinz. “Maybe I should have rested that year.”

Reiser told Heinz dozens of fascinating, lucid old anecdotes. Finally, Heinz asked the money question: Would he do it all the same way, throw away the greatness, the cash, live his whole life in pain (he died at 61) just to play every instant at full throttle?

“It was my way of playin’. If I hadn’t played that way, I wouldn’t have been whatever I was,” said Reiser. “God gave me those legs and the speed, and when they took me into walls, that’s the way it had to be. I couldn’t play any other way.”

There is a cult of playing the Reiser way. Ken Griffey, Sr., played hard, but not crazy hard. But his son, Ken Griffey, Jr., did and paid a high price — a wrist shattered against a wall that required a plate and screws. I talked to Junior about it several times. He said he couldn’t stop, only knew one way.

Nats Manager Davey Johnson grew up in the baseball-as-field-of-honor school, and he’ll never tell Harper to slow down. Davey was about half crazy on and off the field until he started to slow down in his 50s. In that respect, he’s the worst manager Harper could have.

“He’s not worried about the wall or anything,” Johnson said Monday night, right after Harper ran full speed face-first into the right field wall at Dodger Stadium, then lay on the ground motionless, with blood creasing both cheeks from an 11-stitch cut to his throat. “He should know it’s on the warning track and back off, but that’s not his nature. I don’t want to change that. I feel sorry for the wall if he keeps running into them.”

Harper’s reaction, in a tweet, to a play on which he did everything wrong — misplayed a line drive, got turned around and disoriented, then turned a routine double into a triple — was, in my opinion, the worst possible choice.

“I will keep playing this game hard for the rest of my life even if it kills me. I’ll never stop,” wrote Harper.

Reiser once received last rites at the park.

Harper still hasn’t fully recovered from a collision with the wall in Atlanta in April that produced a spectacular bruise and sent him to the bench, then into a hitting slump when he came back rusty. What Harper did on both those plays was not brave or tough or funny or even an example of team-first play. He shouldn’t be encouraged in his folly.

It’s time for Harper to put away childish things. Before they put him away. He can play as hard as he wants everywhere on the field. It will buy him some extra injuries, but that’s all right, if it’s essential to his athletic identity. Batting helmets may preserve him from the worst of the Reiser-like beanings. But walls are entirely different. Walls always win.

Harper doesn’t need to shed his courage. He needs to learn to play the outfield correctly. It’ll take years. Mays was the best outfielder I ever saw. He climbed fences and caught balls 12 feet off the ground. He had a few collisions with other outfielders. But Mays didn’t run into walls. He sensed the warning track, knew every fence and exactly how many feet he had for the maximum combination of altitude at the wall while escaping destruction.

However, Harper may never learn, may not even be capable of learning. Like Griffey, Jr., he may be defined to the bone by the way he plays baseball. He may be the modern Reiser. Let’s hope not.

But if he is, now you know how the story ends, and so does Harper for what it’s worth: In his whole career, Reiser had one — only one — great season.

For previous columns by Thomas Boswell, visit