The One Change That Made Andrew McCutchen Baseball's Best Player

The Pittsburgh Pirates' Andrew McCutchen is baseball's best player. That's not an opinion; it's a fact. Use any metric you want, whether you prefer outdated or cutting-edge statistics. However you slice it, McCutchen's a cut above. Let's start the analysis simply:

McCutchen leads both leagues in batting average at .371. But that's an antiquated stat. Let's look deeper.

McCutchen is also tops in slugging percentage, with a gaudy rate of .651. That's more impressive, but we can look even deeper.

How about wOBA? For reference, wOBA is a catch-all hitting statistic that combines all the different components of hitting into one number.  Basically, it accounts for batting average, on-base percentage and slugging percentage, but weights each number according to its actual run value. Think of it like an on-base percentage that gives extra credit for extra-base hits. An average hitter's wOBA is around .320.

Unsurprisingly, McCutchen leads the world in that statistic as well, with a robust wOBA of .452.

And finally, the mother of all advanced stats: WAR. Wins above replacement is exactly what it sounds like—it measures how much better (or worse) a player is than a replacement-level substitute. It factors in hitting, defense and baserunning. You can read more about it here.

Naturally, McCutchen leads baseball with a WAR of 5.2. Nobody in baseball has been better.

After a historically great month, the 25-year-old center fielder is entering rarified air. Per Yahoo! Sports:

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CF Andrew McCutchen was on one of the great month-long tears in franchise history, batting .455 with 11 home runs and 31 RBI over a 29-game span through Sunday. That was the best 29-game output in the Triple Crown categories since Lance Berkman went .451-11-30 in 2008 with the Astros. It also was the best such output for the Pirates since the majors began recording RBI in 1920.

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But where did all this come from? How did McCutchen, who was definitely an excellent young player, make the leap to being the best one alive?

It's pretty simple: he started swinging more.

In his first three years as a major league player, McCutchen swung at an average of under 40 percent of pitches. Starting in 2009, his swing rates were 39.4 percent, 38.6 percent and 41.5 percent. It's no coincidence that McCutchen was lauded in his first three seasons for having uncommon patience for a player his age. His walk total climbed from 54 in 2009 to 70 in 2010. Then, in 2011, McCutchen walked 89 times.

His plate discipline was among his greatest assets.

But in 2012, McCutchen started swinging. And when he did, he began to terrorize pitchers like never before.

Instead of letting over 60 percent of pitches pass him by, McCutchen took rips at more than half of them. His swing rate of 50.3 percent in 2012 is among the top 30 in MLB. The highest he'd ever ranked before was 123rd in 2011.

That is a jump unmatched by any player in recent memory. It's a sea change in McCutchen's game.

Amazing, MVP-caliber results have followed McCutchen's new aggressive approach.

Of course, if you're not statistically inclined, you could point to McCutchen's financial security as another reason for his breakout season. Maybe normal maturation has something to do with it. Those things could have some influence, but the best explanation is the simplest one.

Andrew McCutchen became baseball's best player by changing one thing: he became much more aggressive.

And if pitchers don't adjust in the second half, the results could be monumental. McCutchen's aggressiveness could lead his Pirates to the postseason for the first time in decades—not to mention earn him the MVP and threaten the Triple Crown. That'd be a big change in Pittsburgh.

In the Steel City, this kind of change is good.