Nationals Manager Davey Johnson is showing signs of wanting to come back next year. (Jonathan Newton/WASHINGTON POST)

On Monday, Washington Nationals Manager Davey Johnson left Ross Detwiler on the mound with the bases loaded in the sixth inning and Arizona’s cleanup hitter at the plate. That’s the spot where the young lefty has always been pulled. Johnson wanted to build confidence and grit. Detwiler escaped, pitched on and won.

On Tuesday, Johnson left Jordan Zimmermann in a scoreless game in the seventh inning after a walk on his 107th pitch. He’s always been hooked then for a pitch limit or because only aces tough out such crises. Johnson wants Zimmermann to be that star. Next pitch: two-run homer; Nats lose, 2-0.

Both decisions illustrate why Johnson will be the manager for the Nats next season.

That’s not a fact. It’s an educated guess, a compelling probability. The Nationals will go through a process after the season to analyze their options. Things can change. A better candidate might be found. But the dots have become so huge it’s impossible not to connect them. Baring an earthquake, Johnson is returning. And it’s a saga that’s gaining a “meant-to-be” quality.

General Manager Mike Rizzo loves the job Johnson’s doing. This week, he raved about how Johnson connects with players and how he appreciates Johnson even more now that he’s seen him in action — especially his ability to develop youngsters while still winning enough games.

Rizzo makes lists of possible managers for next season.

“But that’s a tough list to compile: managers who are better than Davey Johnson,” Rizzo said.

“You mean among available candidates?” I said.

“Living,” said Rizzo, defining his search pool as all breathing humans.

As for Johnson, he’s lifting weights and regaining some of the bulk he lost when complications from a ruptured appendix almost killed him several years ago, leaving him almost skeletal, down 70 pounds at one point. After an off-season heart procedure that reenergized him, he’s even strengthening his arm (also age 68).

“I won’t really be able to show Jayson [Werth] what I’m talking about until I can throw him good enough BP,” he said.

That sounds like a man who’s amenable to one last whirl. Johnson was bitter toward the managing life in 2000, after harsh breaks with the Orioles and Dodgers. But Dum-Dum (because he’s smart) has got the bug again.

Once, if you mentioned the word “manage,” he’d say, “Do I look that dumb?” Now, he loves the job and calls the Nats his hardest-working team.

“The feel in the clubhouse is excellent. Players want to pick his brain and have a relationship with him,” Rizzo said, naming several, including Werth.

The Nats seem comforted by a manager who brings stature to a clubhouse where more high-visibility names, and perhaps big egos, may arrive with time. If you played with Frank and Brooks, got the last hit off Koufax in the Series, beat Earl at gin, learned how to hit 43 homers from Aaron and managed Gooden, Strawberry, Raffy, Cal, Robby, Larkin and Sheffield, then the Nats barely move your one-name star meter.

When the Nats’ ride got bumpy in the past, Rizzo showed up, talked to players and media, as Stan Kasten also did. Maybe it wasn’t needed or always welcome. But it left the impression that since Frank Robinson, Nats managers could use support. At such times these days, Rizzo is invisible. It’s Davey’s room.

In his first weeks, Johnson seemed rusty. A blown 8-0 lead in a 10-9 loss to the Cubs evoked Joe Gibbs calling back-to-back timeouts after 11 years away from the NFL. Johnson took the blame, as he has a few times since then — sometimes deserved, sometimes taking a bullet for a player he tried to extend past his normal role to “develop” him.

Calling out mistakes in public has been a Johnson trademark, including goofs by stars. But he does it analytically, like he’s just correcting a math quiz. The Texas twang, and some positive spin, makes it all seem like he’s just talkin’ ball. So far, the daily blue-penciling hasn’t raised hackles. But will current players still respond to everyday real-time critiques? Will Davey’s big personality take up more room, over time, than players like?

Rizzo will also have to decide if Johnson still has the fire that always marked, and sometimes scarred, him. Maybe less is better. “I think he can still jump in people’s faces, if he needs to,” Rizzo said.

You always find out.

Two years ago, Rizzo hired Johnson as a consultant for the same reason some players are fascinated now: to pick his brain. Rizzo drove Johnson around spring training in his golf cart “so I can look smarter.”

But those who knew Johnson best were virtually certain he would never manage again. He and his wife Susan have been through a lifetime’s worth of trauma in recent years. In addition to his ruptured appendix calamity, one of Johnson’s three children by his first marriage, daughter Andrea, a pro surfer, died at 32. Susan’s adult son Jake, born deaf and almost totally blind, died in May after a period of failing health. The Johnsons adored him.

“We had a beach house in North Carolina. That was Jake’s favorite place on earth,” said Johnson, who for two years was one of the few who could and would care for Jake. “We went there with him every two weeks.”

Even vacations, much less managing, had been out of the question. After Jake’s death, the Johnsons planned trips to Alaska and Paris. Then, unexpectedly, manager Jim Riggleman quit. Susan, involved in charity work, saw it as a sign. It was his time.

“My wife’s a saint,” Johnson said, embarrassed.

She sold her women’s clothing store in Florida and pushed Johnson take the Nats job when the team came . . . begging? Close enough.

Everyone, especially Rizzo and the Lerners, know the combination of serendipity and sadness that made Johnson available just when they needed him. They’ve all waited to see if the mix would click. Storybook final chances sound nice, but not if you can’t cut it as a manager anymore.

“Things sure seem to be going well,” Rizzo said.

And it’s highly unlikely anything is going to break it up.