HOUSTON — The story of the sunglasses that became a symbol for the Washington Nationals’ improbable run to the World Series started in Detroit, on a Sunday afternoon so nice that Gerardo Parra and Fernando Rodney decided to walk to the ballpark. As they approached Comerica Park, they noticed a group of people waiting in line; Bubly, a sparkling water brand, was having a promotional giveaway.

“You want to wait in line for some glasses?” Rodney recalled Parra asking.

“Of course, yeah,” Rodney responded. “It’s free.”

Parra’s shades had clear rims with red lenses; Rodney and starting pitcher Aníbal Sánchez received pairs with yellow lenses. The three immediately decided that the new eyewear should be treated as lucky charms for a team that had steadily turned around its season after a woeful start. The Nationals carried a .500 record into that June 30 game against the Tigers, and their 2-1 win left Washington 1½ games out of a wild-card spot.

Perhaps more importantly, the acquisition, and adoption, of those glasses revealed a clubhouse that was lightening up.

“They kept them on for the game, and we were like, ‘All right, we’re taking things up a notch,’ ” reliever Sean Doolittle said. “They helped change the culture in this clubhouse. May was tough for us, and they’ve helped us kind of walk that fine line of playing loose, having fun, taking the field with a smile on your face but also playing hard and staying focused. The second half of the season has been a lot of fun.”

Parra is secretive with the origin story, but when asked whether Bubly gave him the glasses that afternoon in Detroit, Parra clarified: “No, no, no, they did not give it to me. We got it. We took it from the table.”

“I can’t say,” he added. “It’s special information.”

Even other Nationals have apparently been kept in the dark. Upon seeing Parra, Sánchez and Rodney wearing the glasses in Detroit, teammates asked where they had purchased them and how much they had paid. (A spokesperson for Bubly confirmed that, yes, there was a promotional giveaway at Comerica Park that weekend, and the glasses were free.)

“I was like, ‘Yeah, we got them yesterday at the store,’ ” Rodney said with a chuckle. “They believed it. They believed it because we were wearing them, that’s why.”

Parra promised to tell the full story, if there’s more to it, after the World Series. He is as known for the colorful sunglasses as he is his choice of walk-up music, “Baby Shark,” and he is often shown behind the red lenses in the dugout during television broadcasts. When his glasses started to break on the side, Parra glued everything back in place.

“That’s a great story,” Parra said. “We said, ‘Hey, starting today, we will try to bring good luck to the team.’ And we started to win.”

Rodney admitted that he left his sunglasses somewhere, but Sánchez has stayed as committed to the bit as Parra, who dons his even for night games. If Sánchez feels the team needs a change in juju, he’ll shift his yellow shades from over his eyes to atop his cap.

And the sunglasses? They didn’t initially cost anything, but they’re worth quite a bit now.

“A lot of people ask for it, but I don’t know where they can find them or the production of those kind of glasses,” Sánchez said. “They’re special. That’s why we’re here.”

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