ATLANTA — Max Scherzer, initially thought to be dealing with a mid-back strain, will miss at least one more start after the Washington Nationals gave him a cortisone shot for inflammation in the bursa under the right shoulder blade.

The condition, known as scapulothoracic bursitis, will cause the right-hander to miss two turns through the rotation, at a minimum, instead of the one originally expected. Scherzer, the Nationals’ 34-year-old ace, has not pitched since July 6 and went on the 10-day injured list a week later. He received the cortisone shot Monday and, in Atlanta on Friday, noted that it will take five to six days to alleviate the pain. He cannot work off the mound until that happens, and he cannot make another start until he throws a bullpen session. Scherzer also confirmed Friday that he will not pitch this weekend against the division-leading Braves.

“There’s nothing wrong structurally with the muscles. I’m strong. The scap’s strong,” Scherzer said. “I just have this inflammation in the bursa sac there. Never knew you had one. So that’s kind of the diagnosis that’s got everybody pulling their hair out, has been pulling my hair out.”

When asked Friday whether this was originally misdiagnosed and why Scherzer was at first treated for a strain, Manager Dave Martinez expressed confidence in how Washington’s medical staff handled the situation.

“No, it was the same,” Martinez said of how the diagnosis changed. “It’s just a bursa sac underneath his scap, but you have to treat it as if it’s his back, and now it’s just getting the soreness out of there. That’s basically where we’re at.”

If the pain subsides, Scherzer could return to face the Colorado Rockies in Washington. Or Scherzer could return against the Los Angeles Dodgers next Friday, his regular spot in the rotation. In the meantime, Austin Voth will face the Braves here Sunday. Erick Fedde, still with the Nationals after making a spot start against the Baltimore Orioles, could then go Monday in the first game against the Rockies. Then Stephen Strasburg, Patrick Corbin and Aníbal Sánchez would fall in line before Scherzer is ready to return.

Scherzer is confident in the timeline because of former teammate Shawn Kelley, who dealt with the same injury. Kelley, now a reliever for the Texas Rangers, recently texted Scherzer: “What’s up with your back?” Scherzer, trying to mess with Kelley, told Kelley he had scapulothoracic bursitis. Scherzer did not know that existed before the new diagnosis, which came after he visited a team doctor Monday. Scherzer underwent another round of tests once he didn’t respond to treatment for a back strain last weekend. Then he went to Google and WebMD to figure out how long this would nag him.

But Kelley responded that he recently dealt with that, too. He told Scherzer that the cortisone shot kicked in after five days and got him back to the mound. Scherzer had originally hoped to throw a bullpen on the third day, saying that cortisone shots have worked that way his whole life. Now his expectations have shifted. He has thrown from 90 feet for the past few days and is itching to progress toward his next start.

“Right now I’m on day four of that,” Scherzer said. “I’m trying to stay optimistic and say: ‘Hey, in a couple days I should be feeling really good if this goes exactly as we think it should.’”

This is mostly uncharted territory for Scherzer, who is accustomed to making just about every start. Before the injury, he was leading the league with 129⅓ innings pitched. He has thrown 200 or more, and made at least 30 starts, in each of the past six seasons.

But now Scherzer has to balance his competitive drive with practicality. The Nationals (51-44) wanted him to face the Braves this weekend, since they are still 5½ games back of them in the division. Yet there are still 67 gamesleft in the season and then the playoffs if those go well. Washington needs its best arm — and a leading NL Cy Young candidate — to be available for a pennant race. He was knee-deep in maybe the best stretch of his career, with a 0.84 ERA in his past nine starts since May 22. That includes 94 strikeouts against just nine walks. The Nationals have also won his past seven starts.

They don’t want to jeopardize that in the long term by taking a short-term view. Scherzer has to stomach that approach as much as anyone.

“All I can do is come in here and do my work and get this thing right,” Scherzer said, adding he will pitch in a game as soon as he can throw off the mound. “So, I’m following their protocols to the tee and making sure I’m doing what I need to do, so when I feel good they give the thumbs up of when I pitch.”