"That shows you how tough he is out there, playing through it," Johnson said. "I'm not sure what the recovery time is or anything, but that's a big loss."
After a five-game absence from the starting lineup from July 15-19, Desmond returned to his regular No. 6 spot for this weekend's important series against the Braves. But he told Johnson in the nightcap of Saturday's doubleheader that "it felt like he got hit with a bat in the side."
He did not play in Sunday's 9-2 win.
"It wasn't worse, but I think it was just a matter of the long day. It wasn't getting any warmer and it wasn't stopping raining," Desmond said. "It was probably just enough for the day. But there was no point yesterday where it was like, 'Oh man, I made it worse.' It was just like I was ready to stop."
In a season filled with injuries to key players -- Jayson Werth, Drew Storen, Michael Morse and Wilson Ramos have all missed significant time -- Johnson said "there's no question about it" that this is the most significant loss.
The Nationals recalled outfielder Corey Brown from Triple-A Syracuse. The 26-year-old batted .300 with 19 doubles, seven triples, 21 home runs and 58 RBIs in 95 games for Syracuse, ranking among the International League's leaders in numerous offensive categories.
Desmond's injury almost certainly means that Danny Espinosa will move from his regular spot at second base to shortstop, and Steve Lombardozzi will become the full-time second baseman. That has been the case in the recent weeks when Desmond was nursing the injury.
"I just told Lombo, 'You can throw away that outfield glove. Put it in the back of your locker,'" Johnson said. "I had conversations on the bench with [Mark DeRosa], 'Now you're my backup middle-infielder. Your role is changing. You're invaluable.'"
As far as that switch is concerned, the timing is good, because Espinosa is riding his hottest streak of the season -- batting 11-for-27 (.407) with five RBIs and five runs on the team's recent homestand.
"I'm hoping that I can continue to swing the bat well and fill in for Desi," Espinosa said. "Like I said, he's done a great job. It's hard to replace an All-Star."
DeRosa missed the entire month of May and most of June because of an oblique injury. He said he expects Desmond will feel it until the offseason.
"You just gotta get to the point where you can trust that you can let your swing go," DeRosa said.
Desmond did not miss an inning of baseball from April 19 through the All-Star break, when it was announced shortly before that he would miss the Midsummer Classic because of the issue.
He took that time off but started the team's first two games out of the break in Miami before taking most of the time off before this weekend.
"At the very beginning, it felt like this, and then it loosened up a little bit and I was able to play through it until the All-Star break and went home and rested and felt great in the first initial batting practice back," Desmond said. "Then it kind of came back a little bit and I was waiting for it to go away like it did the first time. It just stayed."
The 26-year-old is batting .286 this season with 17 home runs and 53 RBIs. His home run and RBI numbers lead all Major League shortstops.
"He's been our MVP all year," DeRosa said. "Big hit after big hit. He's basically been the captain of our infield for all of the first half of the season. So to lose him is tough. But we lost Werth for an extended period of time. [Morse and Ryan Zimmerman] both have had their hiccups, and the pitching has held true the whole time. If they hold up their end of the bargain the way they've been doing, I think we'll be able to make do."