ATLANTA -- Ryan Zimmerman had finally started to feel completely healthy, his swing rounding into form after spending two months on the injured list with plantar fasciitis in his right foot.

Until the second inning of Sunday’s 7-1 loss to the Braves, when Zimmerman aggravated the injury while running down the first-base line, trying to beat out an infield single. An MRI exam is scheduled for Zimmerman when the team arrives back in D.C. on Monday, so he was hesitant to speculate on the severity of the injury, but the Nats’ veteran first baseman was frustrated by yet another setback on the field.

“The last three or four days or so have been the best it’s felt,” Zimmerman said. “It kind of started to, not turn a corner where its completely gone, but definitely feel like I can be a little bit more athletic and do some things. But, yeah, it’s frustrating. Been feeling better at the plate and been starting to get back into it a little bit, and then for it to act up again -- we'll see what it says tomorrow and go from there.”

Including his single in the first inning, Zimmerman is batting .302 (12-for-43), with five doubles since returning from the injured list, and both he and manager Dave Martinez had been seeing encouraging signs at the plate.

Zimmerman initially thought Braves third baseman Josh Donaldson caught the ball he hit in the second inning. Once Zimmerman realized there was no catch, he tried to speed up, which is when he felt the injury flared up about halfway down the line, causing Zimmerman to grimace and pull up to the bag in pain. Martinez and head athletic trainer Paul Lessard came out to check on Zimmerman at first base when the ESPN broadcast mics picked up him telling Braves first baseman Freddie Freeman that it was his heel.

After a brief conference, Zimmerman was lifted from the game for Matt Adams.

“It’s hard to tell now,” Zimmerman said when asked for his level of concern. “I’ll be able to answer that question precisely tomorrow.”

Zimmerman has already missed two months this season while dealing with the foot injury, making Sunday just his 33rd game of the season. Injuries have derailed the later stages of his career, and he has played in more than 100 games only twice (2016 and ’17) in the past six seasons.

“We haven’t talked about the diagnosis and all that kind of stuff, but he’s a middle-of-the-order guy that we rely on in RBI situations,” second baseman Brian Dozier said. “And a leader of the team and all that. We need him on the field. Hopefully everything is OK.”