Adam Eaton grabs his left leg after beating out an infield single in the ninth inning. (Mitchell Layton/Getty Images)

The Washington Nationals were in the midst of a spirited comeback, the crowd on its feet, the tying run at second, when the whole thing came undone. After he beat out an infield single to load the bases in the ninth inning Friday, Adam Eaton was suddenly on the ground behind first base, in apparent agony, pounding the ground in pain.

Dusty Baker said he did not have any update on Eaton’s condition after the game, only that the 28-year-old had suffered a “leg” injury, and would undergo an MRI exam Saturday. That the Nationals chose an MRI exam implies ligament, tendon, or muscular damage — as opposed to an X-ray, which are used diagnose a broken bone. That conclusion, however, is merely speculation. No one with the Nationals has said anything specific.

“As you saw, the same thing we saw, it didn’t look too good,” Baker said. “We’ll know something more tomorrow.”

Replays showed Eaton had landed on the base — directly on the base — in a way that curled his ankle behind itself as his leg collapsed around it. After a lengthy delay, trainers carried him off the field with no weight on the leg. The inning resumed, as Chris Heisey replaced Eaton at first base. But should Eaton miss significant time, he will not be so easily replaced.

Eaton was hitting .297 at the time of the injury, and had settled in at the top of the order, allowing Trea Turner to drive in some runs in the second spot, while playing solid defense in center field. The Nationals acquired Eaton in one of the most discussed trades of this offseason, sending two of their top pitching prospects — Lucas Giolito and Reynaldo Lopez — along with one of their 2016 first-round picks to the White Sox in exchange for the spunky outfielder.

“When we traded those guys for him, everyone freaked out and said it was the worst trade of all time and this stuff,” Ryan Zimmerman said. “We got a big-league ballplayer that does a lot of things good … he came over here and did everything expected and more, which is hard to do when you get traded for guys like that and it puts pressure on you.”

Initial options to replace Eaton in the short-term include Michael A. Taylor, who is currently on the roster, Brian Goodwin, currently in Syracuse, or perhaps Rafael Bautista, who leaped onto the big league radar with an impressive spring training. Should Eaton miss months — and importantly, no one has said that he will — perhaps the Nationals will have to look outside the organization for a full-time center field option.

In the interim, his injury sent the Nationals’ clubhouse, invigorated after a 9-1 road trip, into a somber state. Veterans like Jayson Werth and Shawn Kelley huddled after the game, whispering, as others chatted with trainers walking through the room. Postgame interviews were subdued, even moreso than they might be normally after a loss like that.

“It’s just awful,” Max Scherzer said. “Especially when you see the replay, he comes up short of the bag and you see his ankle roll over, his whole leg kind of falls apart. Seeing him in the training room, it’s an awful feeling. You hate seeing your teammates, those guys injured severely. And I think that’s what happened.”