The Post Sports Live crew debates whether opposing players purposefully hit Bryce Harper because they dislike him. (Post Sports Live/The Washington Post)

Last call!

Dim the lights for a second in the locker rooms of all the major league baseball teams that are three to seven games out of the playoff picture with more than a month still to play. For the Indians, Orioles, Yankees, Diamondbacks and Nationals, it’s time to hit the gas or take the pipe. They know it.

“I still think we’re in a pennant drive, not a salary drive” says Nationals Manager Davey Johnson, whose Nats were 101 / 2 games behind Cincinnati for the last wild-card spot Aug. 19, but trail the Reds by seven games and “just” six in the all-important loss column.

The past two seasons underlined one of baseball’s oldest rules: Don’t give up too soon. In the coming days, all these teams will face days when they’ve lost ground and think, “We’re just not going to make it.” GMs will be tempted to make a white-flag trade of a walk-year vet such as the Nats’ Dan Haren.

The late-season chase, even when it fails, is one of baseball’s pleasant bonuses. Fans in towns with successful baseball traditions know that, once you’ve endured the disappointment of falling behind, you get the free ride of sniffing a big comeback but shrugging if it doesn’t happen. Washington has had so few talented teams in 80 years that many fans don’t get what seems obvious to fans of “miracle-comeback” teams such as the 2011 Cardinals, who were 10½ games out of the wild card Aug. 25 but won the World Series, or the 2012 A’s, who went 33-13 to erase a 13-game deficit and won the division.

There’ll be a year, or for young fans several, when the Nats make up, or almost overcome, huge late-season deficits. Each time the odds will be hard against it. But when it does happen, there’s nothing nuttier.

Stats sites do the correct math to give the Nats miserable 33-to-1 odds to make the playoffs. But what simulations don’t capture is the factor that stock market models missed five years ago: The radical “fat tail” outcomes when human emotions, usually fear, distort the bell-curve of “normal” outcomes.

A Wall Street panic and a pennant-race collapse feel similar. But in baseball, they are far more frequent. In just the past two years, six teams have imploded to lose division titles or a playoff spot. It’s tempting to think the team ahead of you “only has to play .500 the rest of the way and we’re dead.” But that’s not baseball. There is no “play .500” button to push.

In ’12, the Pirates, on a 93-win pace, the Dodgers, leading the NL West, and the White Sox, leading the AL Central, had late-season collapses of 9-23, 9-17 and 12-21 to murder their seasons.

This year, the Red Sox, Rays, A’s and Reds are the teams in roughly similar spots. The Pirates are printing playoff tickets and discussing October rotation issues. But they’re just eight games ahead of Arizona in wild-card standings.

Instead of “oh-they-only-have-to-play-.500” lazy-think, plug last season’s collapses into this season’s standings and see what insane possibilities suddenly arise.

In ’11, the Red Sox (8-21) and Braves (8-18) had the ignominious slumps that wouldn’t stop until they were snuffed from the postseason on the last day of the season. Movie script: “It Happens Every September.”

The past two weeks of the season are just as treacherous. That “magic-number” countdown phrase — “we only need to win X games” — is fatal thinking. Far better to be the chaser with only one thought: “We have to win every game.” Last year, Texas ended the season 2-7, lost the division on the final day, then bombed in the wild-card play-in game.

The Nats have squandered chances to get momentum all season, so maybe that’s just who they are this year. But they have one last wide-open chance to have some fun.

On Tuesday, they began a span of 26 games in which they play the 101-loss-pace Marlins 10 times. Fish rookie Jose Fernandez, who leads MLB in ERA but has an innings limit, likely will miss all 10. The Nats also have seven games against the decimated Mets, who just lost the great Matt Harvey for the year and have David Wright on the DL. And Tuesday the Mets traded center fielder Marlon Byrd and catcher John Buck for prospects. Oh, and the Nats face the Phillies six times. They just fired their manager.

Meanwhile, the Reds just lost two of the first three games of a brutal 13-game stretch during which they face the Cards (who own them) three more times, as well as the Dodgers (three) and the Rockies in Denver (three).

“We feel like we’re playing good baseball,” said Tyler Clippard of the Nats’ 13-5 record since a sweep by the Braves doomed their N.L. East chances. “We’re taking it one day at a time because that’s all we can do. . . . We don’t think about any of that [standings] stuff. It’s a moot point.

“The only thing on our minds is ‘finish strong.’ ”

I’d have believed him more except he glanced at the Reds game on television three times as he said it.

The Nats are hitting much better and, all in all, playing less badly than they were three weeks ago. But if they think they are playing well enough to make a true playoff push, they are probably wrong.

“For a while we’ve been healthy and at the talent level we expected at the start of the year. We need to win close to 90,” said Johnson, knowing it takes 22-9 to reach 88 wins. “We survived [earlier struggles]. Now every game we need to play well, like we were projected to play.”

As for the notion that teams ahead of them will necessarily “play .500,” Johnson said, “Don’t take anything for granted in this game. That’s a losing attitude. [If] somebody falls down a little bit, it could be interesting.”

In one league or both, somebody almost always falls down — six such teams in just the past two years. So if they do, who out of the endangered O’s, Yanks, Indians, Nats and Diamondbacks will be prepared to take advantage?

For more by Thomas Boswell, visit