Gerardo Parra has a saying. You may have heard it by now. Since he joined the Washington Nationals in early May, straight off baseball’s unemployment line, the veteran outfielder has found a way to explain just about everything with two simple words.

Getting cut by the San Francisco Giants after a month of little to no production? “That’s baseball.”

Crushing a grand slam in his second game with the Nationals, against the Los Angeles Dodgers no less, at a time when every win felt like finally finding the missing clue? “That’s baseball.”

How about dropping into a weeks-long slump, peeking his head out with a couple of hits this summer, and doing so while the children’s song “Baby Shark” blared over the Nationals Park speakers? Yeah. “That’s baseball.”

“It’s just …” started Parra when asked to expand on this way of thinking. “It’s just, man, I don’t know. It’s just baseball. Baseball changes. Baseball’s crazy. Baseball is baseball.”

When outfielder Gerardo Parra takes the plate at Nationals Park, the children’s song “Baby Shark” blares over the speakers, and fans can't help but join in. (The Washington Post)

Then he smiled because, of course, that left room for another reminder from the 32-year-old: “That’s baseball,” he sung with a laugh before grabbing his mitt, adjusting his “Parra Shark” shirt and jogging through the tunnel and out to the field for batting practice. This was in August. This was before he dropped into a 3-for-49 slump that ended with three hits, a homer and four RBI on Friday night — then a grand slam Saturday. This was before the Nationals clinched a playoff spot Tuesday and, amid the beer-soaked madness, Parra hugged every single one of his teammates, his work here nearly finished, his outlook reverberating one more time.

He snapped selfies. He streamed the party on Periscope. He wound up in the center of a circle as someone put on “Baby Shark” — his walk-up music, his odd way into Washington’s heart — and danced until his face turned red. He is not Max Scherzer, Anthony Rendon or Juan Soto when it comes to on-field contributions. He is not even Tanner Rainey or Michael A. Taylor. If anything, after a strong season as a pinch hitter, this month proved that Parra is a plus defender who still struggles at the plate. But ask anyone in that clubhouse, at any time, and he’ll say this season turned when Parra arrived in Los Angeles on May 9.

It sounds like the sort of cliche a revived team would lean on. But it also may be true.

“This never was about me,” Parra said in August, right when Sean Doolittle walked by him wearing a “Parra Shark” shirt and a custom-made shark headband, the big white teeth clenched into a grimace, the whole get-up a nod to the leader no one saw coming. “This was always about these guys and this team. I’m just being myself.”

Adam Eaton explains the Gerardo Parra effect this way: Imagine the Nationals have a big game they need to win. Their confidence is sagging after a tough beginning to the season. So they sign a hypothetical pitcher who has been in Japan for the last half decade, maybe more, and bring him in to start. He has no idea what the stakes are. He doesn’t know that the team has been losing, who’s on the roster, whether there’s been a history of bad playoff luck or Washington has won five straight World Series titles. He just comes in and throws. And he dominates — “Because of course he’d shove,” Eaton adds, using a baseball term for just that — and the Nationals ride his arm to a victory.

Then they all step back and wonder how this pitcher from Japan was so calm.

“That was Gerardo for us,” Eaton said. “We needed someone who didn’t know what was going on. There is a tendency to start feeling a little sorry for yourself when you’re injured and not winning and the hits aren’t falling or whatever. Gerardo came in with a smile and was like, ‘Why’s everyone so tight?’ ”

The Nationals were 14-22 when Parra first walked into the visitors’ clubhouse at Dodger Stadium. They’d soon drop to 19-31, a season low, before the winning began. And when it did, when Washington posted the league’s best record across a three-month stretch, Parra chipped in on the field while starring off it.

He and Aníbal Sánchez, longtime friends from their native Venezuela, began mandatory dance parties after each home run. They even got Stephen Strasburg to partake after he whacked a three-run shot at SunTrust Park in Atlanta. Parra started wearing orange-tinted sunglasses in the dugout, and still does, before Sánchez and Howie Kendrick joined him with pink pairs. The music that blares in the clubhouse after each win is played off Parra’s phone. He made “Baby Shark” a nightly ritual at Nationals Park, with fans standing and clapping their hands together like a chomp, and it somehow doesn’t end there.

Parra zips into the home clubhouse riding a bright yellow motor scooter most days. He almost always honks his horn to announce his arrival. Sometimes he even whips through the furniture, cutting tight corners in front of lockers, before parking it by Dave Martinez’s office. It’s impossible not to laugh. He wrapped his arms around Strasburg — serious, stone-faced Strasburg — after he exited his start Thursday evening. Others joined in to make it a group hug. And Strasburg, like his teammates, had no choice but to lean in.

Before last season, Martinez’s first as manager, Washington tried to manufacture the loose culture they have now. Martinez brought camels to spring training to tell his team it was time to get over the hump. They had a golf chipping contest after a day of workouts. But it wasn’t real. It wasn’t Parra, a player they took a flier on in May, a player who was cast off by the Giants because he couldn’t hit and didn’t fit into their future.

That’s baseball. That’s what these Nationals needed to hear.