So, how’s that Nationals lineup coming along, Dusty? What’s the batting order look like for Opening Day in less than three weeks?

Dusty Baker’s forehead furrows as if he’s been losing sleep. In fact, the Nationals manager has been waking up when he has an inspiration about how to align and synchronize his weapons.

Few teams entered spring training with more offensive pieces than the Nats. But as the exhibition season progresses and Baker keeps juggling combinations, it is becoming clear that getting the entire Nationals offense to equal the sum of its parts could be the manager’s biggest challenge.

“Oh, it’s complicated,” says Baker. That may be an understatement.

The pretty-on-paper lineup that fans and the Nats’ own front office may have envisioned during the offseason after Adam Eaton was acquired in trade would put start with Trea Turner, who hit .342 last year, then have three left-handed hitters in a row in the No. 2-3-4 spots — Eaton, Bryce Harper and Daniel Murphy. They’d be followed by three straight right-handed hitters — Anthony Rendon, Jayson Werth and Ryan Zimmerman.

“Having three in a row from the same side, then three in a row from the other side just makes it so easy for the other manager to use his bullpen,” Baker said.

In plenty of games, the Nats might face one lefty reliever, who specializes in afflicting left-handed hitters, perhaps in the sixth inning to get those 2-3-4 men, then see another lefty late-game beast in the eighth.

Some have suggested Turner move to No. 2 with Eaton taking the leadoff spot, where he hit as a White Sox. But Baker’s face says that may not happen.

“Trea’s whole thing at the plate last year was being aggressive. And being aggressive on the bases,” says Baker, who was teammates in Los Angeles with current Nats first base coach Davey Lopes in 1976 when he had the freedom to steal 63 bases as a leadoff man. Do the Nats and Baker want to tether Turner? Obviously not.

But if Turner hits second, his aggressiveness may be compromised because he’ll need to take pitches to give Eaton chances to steal. Hittin second would also mean Turner gets fewer chances to steal. You’d often like him to stay on first base to keep the hole on the right side open for the star lefty hitters behind him. And if he does steal second, it lets foes intentionally walk your No. 3 hitter if the situation dictates it. So, if you want to minimize Turner’s impact, just hit him No. 2.

General Manager Mike Rizzo has insisted that hitting three lefties in a row is not a strategic problem if the trio is Eaton, Harper and Murphy “because their splits are basically the same against both left and right-handed pitching.”

But that isn’t true, either over their whole careers or the past few years. Eaton, Murphy and Harper see their career on-base-plus-slugging averages drop by 82, 101 and 147 points against left-handers. In the past two years Eaton has hit 28 homers, but only one against a southpaw.

As a nasty twist, Turner has reverse splits; it’s almost as if he were another left-handed hitter himself. Turner’s OPS was a huge .176 higher last year against righties. And he only hit one of his 13 homers against a southpaw.

How weakened might the Nats be against lefties, like the Dodgers’ Clayton Kershaw and Rich Hill if they began with Turner, Eaton, Harper and Murphy?

In effect, you’d have set up the whole lineup backward, subtracting at-bats from Jayson Werth, who has killed lefties his entire career, especially last year (1.031 OPS), as well as Rendon, who also hits lefties well.

“We may end up needing to have two lineups,” said Baker, who is considering batting Werth at No. 2 against lefties.

Baker revived the seasons of both Werth and Rendon last May when he flipped them in the No. 2 and No. 6 holes. Both got hot, hit well the rest of the year and credited Baker’s intuition.

“A manager has to make tough decisions in every lineup he writes. Until you’re the guy who sits in the last seat on the end of the dugout, you don’t know. He’s got the most thankless job in baseball,” Werth said.

“People look at stats from the outside and just see numbers. They’re not down in the dugout feeling how the game is actually played,” said Werth, going all old school. “Where people hit, who bats in front of them and behind them, influences what kind of pitches they get, the whole approach to attacking them.”

The shocker for Nats watchers this year may be how often Eaton, who cost such a princely prince, hits below the cleanup man despite batting at the top of the order his whole life. In the offseason, Baker ran into White Sox Manager Robin Ventura on a beach in Hawaii and asked him where Eaton could be successful in the order. Ventura believed Eaton had always been stereotyped as a leadoff man because he was small. Eaton even wears a Mighty Mouse T-short under his jersey. But Eaton ’s 52 extra-base hits last season could translate to RBI opportunities down in the lineup.

So, the Nats traded three pitching prospects for someone who’ll spend significant time as a No. 6 hitter? Or, as Baker says, “A second leadoff man.”

Baker is so conscious of 2017 lineup permutations, and adjusting to who is healthy and hot, that he has dubbed Rendon his “glue” player because he can bat anywhere in the lineup.

If Rendon is the glue, then Zimmerman may be the mystery man. “Our lineup is left-handed strong,” Baker said. Which means he needs a bounce-back season from the right-handed Zimmerman, who has pounded left-handers through his career (. 891 OPS). So far this spring, Zimmerman has only one infield hit and has looked late on too many pitches.

Fans love to second-guess lineups and debate the theory of their construction. The Nats will provide a masters’ course. Every key Nat, except Rendon, has a distinct split tendency to hit better against one type of pitching.

So who should bat No. 2? It could clearly be Turner, Eaton, Werth or Rendon. But in the playoffs last year, Baker batted Harper there twice.

When Baker takes his lineups to the plate this year, if he looks like he hasn’t been getting quite enough sleep, there’s a reason. He probably hasn’t.