Having lost a starter and a reliever in free agency, two starters to elbow surgery and opening the season with three others still dividing time between ice bags and bubble wrap, the Braves are exactly where everybody expected through four games.

With the best staff ERA in the majors.

Wait. What?

This time, it was David Hale’s turn.

On Wednesday, he spent most of a flight from Milwaukee to Washington in the airplane restroom with a stomach virus.

On Thursday, “I was just trying to keep food down.”

On Friday, the rookie from Marietta, making his third career start, threw five shutout innings against a Washington team that just scored 22 runs in a three-game sweep of the New York Mets, and the Braves went on defeat the Nationals 2-1 in the opener of their let’s-see-who’s-best-in-the-East series.

“To pitch here before a packed crowd on opening day, it was a lot fun,” Hale said.

No reason for jitters. Nervous rookies are so yesterday. Hale, with his degree from Princeton in operations research and financial engineering (read: economics), figured to be crunching numbers, not batters, until this other career suddenly developed in college, and ligament calamity turned the Braves into a land of opportunity.

The concern in Atlanta was that all of the lost arms, particularly Tim Hudson (free agency), Kris Medlen (elbow) and Brandon Beachy (elbow), would leave the starting rotation too young and inexperienced. The team also began the season without Mike Minor, Ervin Santana and Gavin Floyd (all of whom are expected back within a few weeks).

The starters in the first four games of this season: Julio Teheran (second year), Alex Wood (second year), Aaron Harang (released in camp by Cleveland) and Hale (who made his major league debut in September).

But the Braves are 3-1, and it’s not because of the offense (team batting average: .183). The starters’ collective ERA is 1.09. The pitching staff’s ERA is a majors-leading 1.29. The vagabond Harang took a no-hitter into the seventh the other day.

“You can’t ask for anything more,” manager Fredi Gonzalez said. “(Pitching coach) Roger (McDowell) has done a hell of a job with those guys. Hopefully they can keep doing this until our offense gets rolling.”

Pitchers have worked their way into jams, but they keep finding their way out. The Nationals had eight hits and four walks, but managed only one run. They stranded eight base runners, had two players picked off, had another thrown out at the plate and saw a bizarre inside-the-park home run by Ian Desmond in the fifth inning overturned on replay and morph into a ground-rule double.

Reliever David Carpenter allowed a single and a walk to open the eighth. Then he struck out Adam LaRoche, Ryan Zimmerman and Bryce Harper.

“We’re not always going to be perfect,” Carpenter said. “But our philosophy is just keep grinding. Go into attack mode and see what happens.”

Hale was asked jokingly if the pitching staff was just young and dumb and didn’t realize they weren’t supposed to be doing this well.

“Maybe young. Not dumb,” he said.

Princeton guy.

In the second, with Harper on first and one out, he broke for second, but Gonzalez called for a pitchout (“just a gut feeling”) and Harper was caught in a run down. In the fourth, LaRoche tried to score from first on a double, but was thrown out on a relay by Andrelton Simmons. Then Hale struck out Harper.

In the fifth, with the Braves leading 1-0, Desmond lined the ball down the left-field line, and the ball became lodged between padding in foul territory. But while Justin Upton held up his arms, pleading for umpires to rule a ground-rule double, Desmond completed his 360. Gonzalez asked for a booth review and won.

Amid boos from the crowd, Desmond emerged from the dugout and went to second. Then he foolishly attempted to steal third and was caught in a rundown, which means the Nationals went from a home run to a double to bases empty.

“I was just confused,” Hale said when asked his view of the play. “An interesting way to give up a home run.”

Hale was pulled after five innings. Gonzalez was concerned about his recent illness, some long innings and the fact that Denard Span ended the fifth with a hard line-drive out.

Hale was hit by the virus the day the Braves left Milwaukee.

“It wasn’t a good time to get it, having to be on two buses and a plane — and both bus rides (to and from airports) were 30-minute bus rides, too,” he said. “I stood by the toilet the whole time on the plane.”

Nobody would know Friday he had been sick. Nobody would know the Braves have had any pitching concerns.