Christian Yelich, not Mike Trout, is MLB's best player -- and the numbers show it

Mike Trout is not the best player in baseball anymore.

I know -- that reads like blasphemous clickbait. After all, Trout already has produced more career WAR (72.8) than Larry Walker, Derek Jeter, Tony Gwynn and Ernie Banks. He already has collected more top-two MVP finishes (seven) than Hank Aaron, Pete Rose, Ken Griffey Jr. and Chipper Jones -- combined. But Trout is not the best player in baseball entering the 2020 season.

Christian Yelich is. At least he has beenfor the past season and a half.

Yelich made the 2018 NL All-Star team as a reserve with a batting line (.292/.364/.459) that looked like a facsimile of his career in Miami (.290/.369/.432). And then, seemingly overnight, Yelich transformed into a facsimile of Barry Bonds.

Let's start with the back of the baseball card. Yelich has outperformed Trout by many traditional measures since the 2018 All-Star Game (albeit in 18 more games):

But counting stats and context-free rates is no way to win an argument against today's baseball intelligentsia. We can measure clutch performance using in-game leverage, and in doing so, Yelich surpasses Trout by a sizable margin:

But Yelich plays in a more favorable home ballpark. Weighted runs created plus (wRC+) quantifies run creation and normalizes it for ballpark factors, so we can compare players fairly. Even by that measure, Yelich has been a better hitter:

Conventional wisdom would suggest that because Trout is an established superstar and Yelich is a fairly new one, Trout is still the more feared hitter. But Yelich has seen a lower percentage of pitches in the strike zone than Trout, no matter how we slice the data:

And for good reason. Yelich produces better contact on pitches in the strike zone, and the results reflect that:

Trout led the majors with 49 stolen bases as a 20-year-old rookie in 2012 and has never lost his reputation as a speedster. But Yelich has lapped Trout in the baserunning department, too:

So the evidence is clear: Yelich does more damage at the plate and is more efficient on the basepaths. But we have not been entirely fair to Trout. His control of the strike zone -- perhaps the most important skill in the batter's box -- remains superior:

And so does his defense, at a premium position. While measuring outfield defense is fairly unscientific (and only tracked in full-season samples), Trout edges Yelich in all measures by varying degrees:

WAR should never be the final arbiter of a baseball argument, but in this case, the results are telling. Since the 2018 All-Star break, Yelich has produced 13.2 WAR, 1.3 more than Trout's total (11.9). But again, Yelich played 18 more games during that time. So I performed a WAR per game calculation and multiplied by 162, so the numbers are more recognizable:

Nearly a dead heat, with Yelich just 0.1 WAR ahead. What Yelich gains in batted-ball performance and baserunning, Trout makes up for in plate discipline and defense.

Is a season and a half enough time for Yelich to surpass Trout as the best player in the game? Perhaps not. But one thing is clear: For the first time in a long time, the question "who is the best player in baseball?" has two correct answers.