CHICAGO — Cubs second baseman Javier Baez is naturally lefthanded. At least, that’s the story he’s been fed over the years by his brothers, who say they taught him to play the game as a righty. This way, he could play shortstop growing up, just as they did.

“I don’t believe it,” Baez said recently. “But I do everything lefthanded. I write and eat lefthanded, and I can hit a little bit.”

That may provide at least a partial explanation for one of his uncanny talents on a baseball field. When it comes to applying lightning-quick tags, few in baseball are smoother than Baez, who catches the ball with his dominant hand.

“I’m a lefty and I can do better things with my left hand,” said Baez, whose defensive wizardry helped propel the Cubs to the World Series. “I catch the ball with my left hand, so it’s really easy for me.”

He makes it look really easy. Earlier this season, a fan compiled a collection of Baez’s greatest hits. The breathtaking reel is set to “The Blue Danube’’ waltz. It features behind-the-back swipe tags despite impossible angles, tags on errant throws pulled down just in time, tags applied at exactly the time that the ball is caught.

Though it is not considered one of the five tools, Baez has showcased the game-changing ability of his impeccable timing, body control and sleight of hand. For potential base-stealers, success and failure often is separated by mere milliseconds.

advertisement | advertise on newsday

Every advantage counts. “I’ve never seen a guy tag like him,” catcher David Ross said. “I’ve never paid attention to the tag. I don’t know that many people have ever asked me about a guy’s tagging ability, and I’ve been asked this year more than ever. He’s probably gotten me, I would say, 10 to 15 out. That’s a ton when we’re talking about throwing out guys.”

‘I GOT REALLY GOOD AT IT’

From his earliest days playing baseball in his native Puerto Rico, Baez has always adhered to advice he heard long ago. When covering the bag, he wants to beat runners to the spot, allowing him multiple options to apply the tag. He’s not beyond deking opponents.

“Sometimes, when I fake that the ball isn’t coming, some runners kind of slow down,” Baez said. “It helps me and the catchers a lot . . . I worked when I was young when I was playing shortstop to be early to the bag and act like the ball wasn’t coming. Then at the last second, just drop the tag. I got really good at it.”

While Baez’s actions around the bag can be practiced, he believes that his quickness and toughness with his glove is natural. But whatever its origins, he has used that ability to distinguish his own work in the field.

Baseball videos

“He’s the best I’ve ever seen at being able to have his body under control and get the ball down and tag that guy,” Ross said. “He lets the ball travel so well and he’s able to just anticipate the flight of the ball, and it goes right into his glove.”

Baez has been particularly adept at not wasting any body movement. He often has caught a throw and applied a tag in one fluid movement, sometimes while he himself is still in motion.

“There is no stop and then movement,” Ross said. “It goes right into the baserunner. I’ve never seen anybody as good as he is. I don’t think many people have watched that or talked about it. It’s definitely something that’s paid more attention to this year because that’s how good he is.”

‘‘THE QUICKEST HANDS THAT I’VE SEEN’

advertisement | advertise on newsday

Adding to the degree of difficulty is the very nature of tag plays at the bases. Every throw is slightly different, as is every baserunner’s speed and ability to execute various slides around the bag. Even with those variables, Baez consistently makes magic with his glove hand.

“It’s just God-given, man,” Cubs shortstop Addison Russell said. “You can’t practice those plays. All those plays are just done on the fly. You don’t know which way guys are going to slide, you don’t know which way the ball’s going to take you. He has a sense of direction, a sense of quickness, especially the quickest way to tag that person, he has a good sense of that.”

Indians shortstop Francisco Lindor recalls seeing that sixth sense from his earliest days of competing with Baez. Both left Puerto Rico for Florida, where they became high school stars and close friends. Even then, Baez showed the ability to instinctively position himself based on every type of throw and situation.

“He’s got some of the quickest hands that I’ve seen,” Lindor said. “If you’ve seen his bat, his bat is super-quick. His hands are just as quick. He’s always been like that, real quick at tagging, real quick at transferring the baseball, quick with his hands. I don’t know how he does it, but he’s got it. It’s God-given.”

Lindor got reacquainted with that ability in Game 1 of the World Series, when he broke for second base. As he approached the bag, about to begin his slide, Lindor spotted Baez cutting across him.

advertisement | advertise on newsday

“He caught the ball,” Lindor said. “And I felt the wind.”

Convinced that Baez had missed, Lindor popped up and thought he had the base stolen. He was wrong. Later, he said replays showed that the laces of Baez’s glove had touched him before he reached the base. Baez had prevailed again — another baserunner caught with the help of the fastest hands in baseball.

“The umpire said ‘out!’ ” Lindor said. “I’m like, ‘Oh, my God.’ That was pretty quick. I didn’t see him, but I felt it.”