For three quarters of this topsy-turvy 2020 season, Fernando Tatis Jr. was the National League MVP, and there wasn't much debate. Tatis was the five-tool superstar leading arguably the most exciting team in baseball to its first postseason in 14 years. He was a force at the plate, on the bases and at shortstop.

Then, with the award almost within his grasp, Tatis’ candidacy took a left turn. He slumped, for the first time, and the rest of the field closed the gap. Other serious candidates emerged -- including one to his right in the Padres’ infield.

Entering the season’s final day, Tatis is no longer the consensus favorite. That distinction belongs to Freddie Freeman in Atlanta. Tatis might not even finish tops on his own team; Manny Machado’s case should merit consideration.

But Tatis is clearly an MVP-level talent, and he’s playing like it again. Just in the nick of time for the playoffs, too.

In the Padres’ 6-2 victory over the Giants on Saturday night, Tatis went deep for the second time in as many nights, demolishing a Johnny Cueto hanger to left-center. It was Tatis’ 17th homer of the season, tying him with Atlanta’s Marcell Ozuna for the most in the National League. Tatis is vying to join Fred McGriff as the only NL home run kings in franchise history.

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“He's special,” said Padres manager Jayce Tingler. “He's fast, he runs the bases well, his baseball IQ is off the charts. He can beat you going the other way, he can beat you with a bunt, he can beat you going oppo, driving the ball out of the ballpark. ... You're getting a premier athlete out there. He's just dynamic.”

Ultimately, Tatis' candidacy was damaged, perhaps irreparably, by a 10-game stretch prior to this series. He batted .162 without any homers and posted a 15 wRC+. At the same time, Freeman, Machado and Mookie Betts surged. Tatis, however, seemed to embrace those struggles.

“This is part of the game, man," he said earlier this week. "The struggles that happen is what it's about. This game is about approach, and how can you bounce back from the other day.”

The fact that Tatis could endure that level of struggle -- in a short season, no less -- and still find himself in the MVP discussion is a testament to the impact he made in his first 45 games. He was, and still is, the Padres’ spark.

Tatis might no longer be the MVP favorite. But he has a case, and it's predicated on an unlikely aspect of his game: his defense.

A season ago, Tatis was a liability at shortstop -- to the point where questions arose about whether he'd be able to stick there. Those questions are long gone. Entering play Saturday, Tatis was worth six Outs Above Average, according to Statcast. That mark trails only Red Sox center fielder Jackie Bradley Jr. for the best in baseball.

On Friday, Tatis was asked what he's most proud of this season.

"Just the way I've managed myself on defense," he said. "That was my goal since Spring Training, since that time when everybody was dogging if I was going to be able to stay at shortstop or move to the outfield. So I worked pretty hard on that area, and the work has paid off."

How does Tatis' defense apply to the MVP debate? That's for the voters to decide. It's basically the crux of the debate.

Freeman has contributed the most offensive value, by far. Machado and Betts have also been worth more than Tatis offensively. On top of that, Freeman, Machado and Betts are all outstanding defenders at their respective positions. Gold Glovers, even.

But offensive production from those positions is inherently less valuable than it is at shortstop. Look at it this way: if you’re looking for an impact bat, it's generally a lot easier to find one at first base or in right field.

But a shortstop hitting .279/.366/.577, leading the league in homers, near the top of the league in steals, playing elite defense, too? Those don't come around very often.