The Games Will Come Back. The Moments We’ll Miss Are Already Gone.

The sports seasons of 2020 are about to take a place in the realm of what if.

Are we left to imagine Pete Alonso, the Mets’ bear of a first baseman, crashing another 50 home runs? Will we pass the summer arguing how many wins the new Yankee Gerrit Cole might have racked up? How many goals the swift-skating David Pastrnak might have scored for the Bruins in the playoffs? Will regular-season boo birds ever get a chance to remind the Astros they were cheats?

Two months ago I wandered into the Los Angeles locker rooms of the Clippers and the Lakers, two of the best basketball teams in our corner of the cosmos cohabitating in one building. I asked about incipient rivalry and all of them said: Wait until the playoffs and hope for a fabled Western Conference finals, LeBron James trying to school Kawhi Leonard, Paul George feinting, taking Anthony Davis off the dribble.

Just wait.

Absent a virological miracle, this may all be left to fantasy.

A virus has accomplished what even World Wars could not. Our major sports — basketball, hockey, soccer and baseball — are shelved for a month or two or perhaps a full season. We are now a quarantine nation, and our sports teams are shuttering alongside us. The N.B.A. announced Wednesday it was suspending games. Hockey, soccer and Major League Baseball have followed suit.

Statistical asterisks might attend to careers forever. For older players, like a transcendent James in the late autumn of his N.B.A. career, this will be time perhaps never recaptured.

There may be tightfisted holdouts, though not the N.C.A.A., which bailed on its winter and spring championships on Thursday afternoon. To watch a daughter or son play high school or college sports is to empathize with their desire for one more play, one more game. In service of athletic achievement, these people may still crowd into locker rooms and exchange sweaty elbows beneath the basket as referees and coaches and locker room attendants move among them.

To try to describe that scene is to recognize its folly.

We remain a nation half-aware of its sickly status. Leagues cancel games, governors enforce bans on large gatherings and Broadway theaters close. Yet California’s governor, Gavin Newsom, initially let the Disney Corporation continue to pack crowds into its amusement park before reconsidering and ordering it closed. And the Trump administration continues to let cruise ships set sail.

We sports fans are left with our awareness of what will be lost. My sons, Nick and Aidan, and I are lifelong Mets fans, which is to describe hope and despair in a tango. Spring is our favorite season, a time of fantastic prediction and hope without enough games for a proper losing streak. That is taken from us.

Before I get too maudlin, let me posit an upside. ESPN reported that the Knicks owner, James Dolan, had argued against suspending the N.B.A. season. He apparently took the view that a quarantined populace could never get enough of his truly wretched basketball team.

The league, thank goodness, overruled him.

To make sense of all this, I called Dr. Thomas R. Frieden, the chief executive of Resolve to Save Lives, a former New York City health commissioner and President Barack Obama’s director of the Centers for Disease Control and Prevention. Frieden cannot guarantee a canceled N.B.A. season — any canceled season — will make a huge difference; he is sure only that if “this virus is bad and if we didn’t act, that would be indefensible.”

He divides closures into gray areas and no-brainers. Madison Square Garden, Staples Center and similarly large amphitheaters fall into the latter category. “These arenas cannot have spectators,” he said. “That would be completely irresponsible.”

What of outdoor sports? He paused. Sunlight, he noted, is a fine disinfectant, and transmission is much lower outdoors. If baseball and soccer games are played in daylight — who could object to that? — and not under a dome, he sees a window for safe play, even if fans have to remain at home on their couches.

Lost games will exact great cost. Closed arenas mean lost ticket, television and radio revenues. Sports profits and salaries are munificent, and one cannot survive without the other. But Frieden told me we have no choice. “The more we can tamp down the epidemic,” he said, “the more quickly we can protect the economy.”

Perhaps the greater loss in the season of 2020 will be those for whom the hourglass will run out of sand.

Ryan Zimmerman has had a 15-year celebrated career with the Washington Nationals, and last season he finally played in a World Series, hitting a home run and holding aloft a championship trophy. He gave thought to retirement but returned for perhaps a final run with the only team he has ever played for.

Is this how it ends?

Carlos Vela, the Mexican forward for Major League Soccer’s Los Angeles F.C., is still swift and brilliant at 31. But a lost season is lost time. And what of LeBron James? At 35, he is playing one of his grandest seasons, his court smarts compensating for any athletic erosion. James will return when the N.B.A. does, but who is to say if age will finally track him to the ground?

And what of the Milwaukee Bucks, the finest team in the East, and their transcendent star Giannis Antetokounmpo, who is so intent on dethroning James? Generational feuds, the hunger of the young to vanquish ruling stars, lie at the heart of sport. We had good reason to anticipate such a matchup this spring.

That, too, could be dust to virological dust.