Mom said it. Little League coaches reinforced it.

Baseball is just a stupid game, in spite of the way Bob Costas, Kevin Costner and the windbag sitting next to you at the bar have tried to romanticize it over the years.

It has never actually stopped a war or created harmony in a dysfunctional family. Batting .643 with the bases loaded in September has never proven anything about a man’s courage or worth.

That triple-scoop of Death By Chocolate tastes the same to a kid whether his team won by virtue of a walk-off home run or lost 49-3 by the mercy rule.

Now would be a splendid time to remember all this, particularly if you’re a person whose mental health rises and falls with every triumph and travail of the Boston Red Sox.

What was easily the most abysmal August in my lifetime morphed into a sickening September on Friday night.

Jon Lester, one of those pitching prodigies Theo Epstein knew better than to deal for a soulless, veteran role player at the trading deadline, has cancer.

Suddenly losing five in a row to the New York Yankees and filling out a lineup card that would make a Kansas City Royals fan snicker don’t seem like such a big deal.

Twenty-two, mentally tough and physically fit, Lester stands a better chance of beating the daylights out of anaplastic large cell lymphoma than would your Uncle Charlie or your Aunt Clara.

The company line is that the lean left-hander will be back throwing bullets by spring training, as if that were apropos of something.

I hope they’re right, to the extent that it means Lester would be done with chemotherapy and fit to reclaim his place in the lineup as an everyday player in the game of life.

But should anyone care how this mind-numbing news affects the baseball franchise that happens to sign Jon Lester’s paycheck? No way.

It’s chilling how much can change in a little more than two weeks, isn’t it?

Sixteen days ago, there was a realistic thought that the Red Sox could overcome their summer swoon and prevent the Yankees from annexing the American League East title for the first time in nine years.

Sure, we wondered why in the name of Jeff Bagwell that Epstein seemed to pull a Rip Van Winkle, put his cell phone on vibrate and leave it on the nightstand while Bobby Abreu and Cory Lidle ended up in pinstripes. But hope remained alive.

Hope now sounds like a much different word. Being eight games in George Steinbrenner’s rearview mirror, seeing Kevin Youkilis run around like a bullfighter in left field and penciling in Mark Loretta as designated hitter aren’t all that undignified, in the grand scheme of things.

Lester’s life-altering illness comes on the heels of hearing that the face, voice and soul of the franchise, David Ortiz, has been hospitalized twice with inexplicable heart palpitations.

Hey, I’ve had them. They’re usually harmless. But they aren’t something you want happening every day when you have a wife and kids counting on you.

And really, those are the only people who should be counting on David Ortiz, on Jon Lester, on anyone.

These are grown-ups playing a kids’ game. Every once in a while, the Good Lord throws us a curve ball to remind us that baseball is precisely that. Hopefully, He’ll cut the Red Sox a break and throw them straight change-ups the rest of this sad season.

Too many of us, myself included, wept for joy and cracked open a bottle of bubbly two autumns ago when hell froze over and the Sox captured that elusive world championship.

Maybe this morning we’ll shed a tear or two for the right reasons. As for that champagne we set aside for this October? Well, it might be worth keeping on ice until the winter and popping the cork when we get the word that Jon Lester is cancer-free.

Kalle Oakes is a staff writer. His e-mail is [email protected].