The fantasy of any sports always includes the omniscient fast-forward and rewind buttons of memory. Oh, to be an old Brooklyn Dodgers fan and be able to travel back to Oct. 3, 1951, and whisper into Ralph Branca’s ear: “Maybe go with the curve on this one, Ralphie.”

Oh, to be an old Browns fan, to travel back to old Cleveland Stadium on Jan. 4, 1981, and sidle up to Brian Sipe in the huddle as he’s calling for “Red Right 99” and scream in his ear hole: “Remember what Coach Ruttigliano said! Throw the ball in Lake Erie!”

Oh, to be a Mets fan. And to travel back to just past 11 o’clock on the evening of Nov. 1, 2015. And to be a fly on the dugout wall as Terry Collins approaches Matt Harvey, who has thrown the most important eight innings of his life — nine strikeouts, one walk, four hits, and zero runs in Game 5 of the World Series.

The Mets led, 2-0. Jeurys Familia was warm in the bullpen — and that was before the term “Jeurys Familia was warm in the bullpen” gave Mets fans instant night sweats — and Collins wanted to congratulate Harvey for a job well done, wanted to shake his hand, maybe tell him hey, you never know, I may need you to get an out three nights from now in Game 7.

Harvey never let him get that far. He pled his case.

“You’ve got to let me go out there. This is my night, this is my game! I’m fine, you got to let me have this game.”

Collins admitted later he knew better. He knew better.

But Collins was also a guy who loved old-school, blood-and-guts baseball. It went against every instinct he possessed. But he relented.

“You got the first two guys,” Collins said.

And, well, if only you had a pause button, too, to lean on and allow everyone to take a deep breath, to allow everyone to ignore the electricity that bounced all around Citi Field in that moment, Mets fans hungry for the Dark Knight to seize the moment he was born for.

Pause it there. Think about it. Think hard about it.

The Angels designated Matt Harvey for assignment Friday, and the news may not have been a surprise — he was 3-5 for Anaheim this year, pitched to an almost impossible-to-believe 7.09 ERA — but it is sobering nonetheless, given what a prominent piece of New York’s baseball pie he was not so very long ago.

Memories of Harvey mostly focus on the 2013 season, when he exploded on the scene, when he was a Sports Illustrated cover boy, when his starts became civic happenings, when he started the All-Star Game … and when, by September, he was prepping for Tommy John Surgery. And that was a magical moment in time, a zeitgeist of the highest order.

But the essence of Harvey was the conversation in the dugout that first night of November, nearly four years ago. He’d come back from Tommy John surgery and been superb in 2015. He’d found some fire at the end of the season when, after resisting the Mets’ attempts to limit his workload at every turn, he talked about ending his season early. He blew off the Mets’ mandatory practice before the NLDS. Already, the first hints of his fallibility were in play.

But that moment in the dugout … that is why Mets fans loved Harvey.

“Give me the ball,” he demanded.

And the ball was given to him.

Everything that has happened to Harvey — and to the Mets — in the minutes, weeks, months and years since may have happened exactly the same way anyway. We’ll never know. This we do know: If you could rewind to that moment, be that fly on the dugout wall, and ask Harvey and Collins to think about this all a little more …

Well, wouldn’t you?

Vac’s Whacks

I could honestly listen to Buck Showalter talk baseball all day and all night, so it would be a welcome transaction to see him regularly on either YES Network or the Mets’ manager’s office, whichever he likes better.

Of all the amazing things that have happened on my television lately commemorating the 50th anniversary of the moon landing, my favorite is this: HBO re-broadcasting and streaming “From the Earth to the Moon.”

If you haven’t yet, make sure you watch “The First Day,” Jonathan Hock’s remarkable ESPN follow up to his “30-for-30” on Chris Herren, “Unguarded.” It will be worth your time, believe me.

I think any list of “coolest living Americans” probably has to lead off with Buzz Aldrin, Michael Collins and Chuck Yeager. Don’t you?

Whack Back at Vac

Kenneth Meltsner: Let’s be honest: Travis d’Arnaud is doing more for Met fans now than he ever did during his time in Queens.

Vac: I understand his career here was disappointing. But it should always be remembered his best time as a Met was October 2015. Not bad timing.

Avi Masliansky: Imagine Dwight Gooden and Darryl Strawberry and no drugs? As Sam Spade said at the end of “The Maltese Falcon,” it’s “the stuff that dreams are made of.”

Vac: For Mets fans of a certain vintage, it’s impossible to stop imagining that alternate universe.

@tonyg_nj: Hey, Tanner Boyle had spunk, Ahmad could bunt, Amanda could pitch, Rudy Stein reached base any way possible and Kelly Leak almost gave Vic Morrow a heart attack. And don’t forget Timmy Lupus being Endy Chavez before Endy Chavez!

@MikeVacc: When a throwaway quip linking the Twins and Chico’s Bail Bonds can elicit such golden memories of “Bad New Bears” days past … then my job here is done.

George Hourican: Thank you for telling the story of Michael Yalango, and for reminding us that sports really can serve a higher purpose sometimes. I had a similar experience, listening to Super Bowl III, though I was lucky enough to be stationed stateside at the time. Still allowed me to feel like I was home for a couple of hours, though.

Vac: Having the privilege of telling Michael’s story last week is one of the reasons why this remains, bar none, the coolest job in the world.