Wilson Ramos tore the anterior cruciate ligament in his right knee Monday. (Andrew Harnik/Associated Press)

When the man so sturdy they call him “the Buffalo” crumpled in agony Monday, the worst outcome immediately felt like the only possible outcome. Washington Nationals Wilson Ramos does not crumple like that unless something is very wrong.

Hundreds of foul tips and balls in the dirt, and dozens of base runners, have bounced off Ramos before, some of which left him doubled over in pain, but none of which stunned him quite like this. An MRI exam Tuesday morning confirmed the Nationals’ fears, revealing a tear in the anterior cruciate ligament in his right knee, Nationals Manager Dusty Baker said. Ramos is done for the season, and he will leave a gaping hole in the middle of the already aching Nationals lineup.

Ramos will need surgery and will be seeing doctors this week to determine when he will have it. His season is over, and because ACL injuries generally take six to nine months of rehabilitation in the best scenarios, he may not be ready for spring training or the start of next season either.

“I just talked to him a few minutes ago. He’s upbeat about things,” Nationals Manager Dusty Baker said. “He knows that other guys have come back from this. I told him about Adrian Peterson [who came back from ACL surgery in nine months]. He didn’t really know who I was talking about. At least he doesn’t have to run through the line and stuff.”

Ramos, in fact, is one of those players who has returned from a torn ACL. He tore the same one in May 2012, and it cost him the rest of the season. This one may cost him more than playing time, because the 29-year-old will be a free agent after this season. He turned down an offer of three years, $30 million from the Nationals earlier this month. In this market, for one of the most productive offensive catchers in baseball this season, that offer seemed low.

Now, Ramos may have trouble getting that much, and his injury leaves the Nationals to decide whether or not they would be willing to pay him $16.7 million — this year’s qualifying offer — for part of next season. If they do not, they would not receive a draft pick if he signs elsewhere.

“We just got the diagnosis,” Rizzo said. “We’re going to see what the doctors say, and we’ll make our assessments after that.”

More immediately, the Nationals now turn to catchers Jose Lobaton and rookie Pedro Severino for the playoffs. Both are better defensive players than Ramos. Lobaton is known for his ability to frame pitches. Severino is the Nationals top catching prospect because of his glove, not his bat — though his offensive consistency has improved because of a “more efficient” swing, Rizzo said. The Nationals also recalled catcher Spencer Kieboom from Class AA Harrisburg — a.k.a. his sofa, where he was watching football and the presidential debate when he got the call — which means every player on their 40-man roster is active, and they still have three catchers for the final week of the season.

But Lobaton is banged up, too. He was on the disabled list with left elbow tendinitis earlier this season, a condition for which he got a cortisone shot in late July. The discomfort has never entirely subsided and is more of a problem when catching pitches than throwing. He also twisted his ankle two weeks ago.

“My ankle has been better. I don’t want to say great, great. But it’s good to play,” Lobaton said. “I haven’t played back-to-back or three or four in a row since — I don’t know, early in the season? But I’m ready. I’m always ready. Whatever happens, I’ll be there.”

Neither Baker nor Rizzo would commit to Lobaton as the everyday starter at the moment, in part because that ankle bothers the 31-year-old catcher more when hitting right-handed. Rizzo indicated the Nationals might match up over the last week of the season, in which case Severino would likely play against lefties and Lobaton against righties. Lobaton has 17 plate appearances against left-handed pitchers this season.

“All of our catchers are very good catchers. It’s just that he is not only the top offensive catcher on our team, a big part of our offense, he’s one of the top offensive catchers in baseball,” Baker said. “We’ll really miss his offense. I think Loby and Severino can replace [him] on defense, but it’s up to some of the other guys to offset his loss on the offensive side of the ball.”

Ramos will finish his season with a .307 average, nearly 80 points higher than last year’s. He will finish with an .850 OPS, more than 70 points higher than his previous career high. His 148 hits, 80 RBI, and 22 home runs are also career highs.