But they actually lost much more than that.
First baseman Daniel Murphy suffered a Grade 2 MCL tear and is done for the season, a source familiar with the situation told ESPNNewYork.com's Adam Rubin. No surgery is required, but there is a four-month recovery period.
Both Murphy and shortstop Jose Reyes -- two of the team's top hitters -- left the game early due to injury.
Murphy, who entered as a Sunday's game as pinch hitter in the sixth inning, left with a serious injury to his left knee. Braves left fielder Jose Constanza slid into second base on a steal attempt in the top of the seventh and his spike collided with Murphy's lower leg.
Meanwhile, Reyes left in the bottom of the second inning with stiffness in his left hamstring, which he first felt while running out a ground ball in the first inning. The All-Star shortstop suffered a strain to the same hamstring last month, which caused him to miss 16 days.
"At this point it looks like a mild pull of his hamstring. If you recall, that was the same level of injury as the last time," Mets GM Sandy Alderson said after the game.
Alderson preferred to withhold judgment on Reyes' injury because the Mets had yet to receive results of an MRI as of late Sunday afternoon, but a source familiar with the injury said Sunday night that Reyes had the MRI and it is not believed to be anything more severe than hamstring tightness in line with Alderson's description of "a mild pull."
As for Murphy, Alderson said he "certainly" will be placed on the disabled list. The only good news was that X-rays on Murphy's knee revealed no fracture. The Mets sent Murphy to the Hospital for Special Surgery in Manhattan Sunday evening for an MRI.
"At this point, his knee was definitely injured, let's wait and see what the MRI tells us," Alderson said.
As a pre-emptive move, the Mets are recalling shortstop Ruben Tejada from Triple-A Buffalo in anticipation of placing Murphy on the disabled list.
No one in the Mets' clubhouse felt there was any malicious intent behind Constanza's slide into Murphy's knee, though manager Terry Collins noted that the Mets' regular first baseman was in "a lot of pain" after the collision.
"All he was saying was 'Get me off the field' -- that's all he kept saying, was 'Get me off the field, get me off the field.' [Trainer Ray Ramirez] tried to get him calmed down. You could tell he was hurting," said Collins, who added that he was "sick to (his) stomach" for Murphy, who tore his right MCL last June while in Triple-A Buffalo and missed the remainder of the year.
As for Reyes, the shortstop was slow running to first after hitting a grounder to third in the first inning. He then struggled on a ground ball up the middle in the second. He was removed for pinch hitter Willie Harris in the bottom of the inning.
Alderson pointed out that Reyes' injury Sunday could be "the same level" of the Grade 1 strain he suffered in early July. Reyes was out July 3-18 due to that ailment.
The 28-year-old is no stranger to nagging hamstring ailments.
A right hamstring injury limited Reyes to just 36 games in 2009. In 2004, he played in only 54 games because of various leg injuries that were so bad the Mets tinkered with changing how he runs.
Collins was asked on Sunday if the Mets can do anything differently to keep Reyes on the field.
"I don't know what to say accept this is not a fatigue factor. ... He's only been out two weeks from the two weeks that we were off," said Collins, also noting that Reyes loosens his legs before each game.
Reyes will be a free-agent at the end of the season. So if the injury is significant, it could affect his value. The Mets elected not to trade him at the deadline, presumably opting to plan on putting together a competitive bid to retain his services.
Losing both Reyes and Murphy for any extended period of time would further cripple the Mets' chances of competing for a wild-card berth.
They lost two of three to the Braves over the weekend and enter play Monday nine games behind Atlanta in the wild-card race.
Of course, Reyes and, to a lesser extent, Murphy are two reasons why the injury-ravaged Mets (56-57) have managed to hover around .500 into early August.
Reyes entered play Sunday hitting an NL-leading .337. Murphy (.318) ranked fifth in the league.
Sunday's ailments were two more in a long line of injuries to Mets starters in 2011. Reyes, David Wright and Ike Davis have missed significant time due to injury. Starter Chris Young is out for the season with a shoulder injury and Johan Santana has yet to return from shoulder surgery that was completed last September.
Collins said on Sunday that he'd never been around a team that has dealt with more significant injuries to key players.
"I've never seen it," Collins said. "There might be a time which I went through in Anaheim in 1999 where we lost some guys for a long period of time. ... But nothing like this, not in the two years I've been here."
Ian Begley is a frequent contributor to ESPNNewYork.com. Information from ESPNNewYork.com's Adam Rubin was used in this report.