All it took was an ounce of doubt from Jorge Mateo.

When Anthony Santander saw the Orioles shortstop working his way through a sudoku puzzle in the clubhouse, crunched over a table with his eyebrows scrunched in concentration, Santander asked what Mateo was up to. And once Mateo explained, he said those fateful words to Santander: “You’re never going to finish.”

“And he said, ‘Oh? I’m never gonna finish?’” Mateo recalled about a week later, sitting across from Santander in the visitor’s dugout at Wrigley Field in Chicago.

That was all Santander needed to become invested in sudoku, beginning a daily competition with Mateo and a few other Orioles in the clubhouse. There’s nothing on the line besides bragging rights, but Santander and Mateo still race to finish the puzzle with a flourish of an autograph.

More often than not, it’s Mateo who walks to Santander’s locker first to show off the winning sheet, which requires that every row, column and 3-by-3 box in a 9-by-9 grid contains the digits 1 to 9 without repeating. But Santander is bound and determined to make up ground.

“I think I’ve won like only once,” Santander said. “There’s a lot of tricks. I haven’t found them all yet.”

Santander picked up his folded sheet of paper as he sat at his locker in the visitor’s clubhouse at Wrigley Field with the sudoku board half filled in. In one box, he pointed out how he was still missing a five and an eight, but he was stumped as to where they went. As soon as a nosy reporter walked away, Santander buried his head back into the game, pencil pressed to his forehead.

That’s the scene frequently in the clubhouse, with Mateo and Santander engrossed in their pregame competition.

“It’s good for the brain,” Santander said. “It’s a brain game.”

That’s part of the reason Mateo began playing sudoku in the first place. While in the clubhouse in Boston, he was reading a book when he noticed the printed pages of sudoku laying on a table. He already knew how to play, but Mateo decided to challenge himself to complete the game every day.

Santander soon joined, and Cedric Mullins and Ramón Urías are also occasional participants.

“Sudoku, you’ve got to think every number,” Mateo said. “You don’t just put a number in, you have to think about it. It’s like baseball. You don’t want to swing at every pitch. You think when the pitch is coming, and you just focus on that pitch.”

Later, in the dugout in Chicago, Santander said he finished his sudoku board about two minutes after that nosy reporter departed his locker. Perhaps the questions held him up in his hunt to beat Mateo — but Mateo batted that idea aside.

“I’m the teacher, Papi,” Mateo said as Santander laughed. “The teacher never loses.”

But Santander is still on the hunt.

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