Fans hold up signs in support of Aaron Judge of the New York Yankees during the 2017 Home Run Derby. (Rob Carr/Getty Images)

Spoiler alert: Aaron Judge is good at hitting home runs.

The 25-year-old slugging phenom is the first rookie to win the Home Run Derby outright, finishing Monday night’s contest with 47 home runs, including an absolute bomb of 513 feet off the glass beyond the left field seats. He set a New York Yankees single-season rookie record with 30 home runs this season, passing Joe DiMaggio’s mark of 29 set in 1936. Judge also joined Roger Maris and Alex Rodriguez as the only Yankees to hit at least 30 home runs before the all-star break. And he is just the second rookie to hit at least 30 home runs in the first half of the season, with a realistic chance to break Mark McGwire’s single-season rookie record of 49 home runs recorded in 1987.

That home-run hitting power has made Judge the most valuable player in baseball this season, producing 5.5 wins above replacement during the first half of the season, more than aces Chris Sale of the Boston Red Sox (5.3 fWAR) and the Washington Nationals’ Max Scherzer (4.4 fWAR) plus Houston Astros second baseman Jose Altuve (4.4 fWAR).

And that’s not even the most impressive part of his season. Judge’s major-league-leading OPS (1.139) is 94 percent higher than the league average, giving him the chance to join Shoeless Joe Jackson as the only rookies in MLB history to qualify for the batting title with an OPS that high or higher than the rest of the league. After adjusting for league and park effects, Judge is creating runs at a rate that is almost two times the league average (197 wRC+), putting him within striking distance of Bob Hazle (207 wRC+ in 1957), owner of the most productive rookie season of all time.

There’s just one problem: Judge’s luck has to hold out for an entire season, and that’s easier said than done.

Judge has a robust .426 batting average on balls in play, a rate significantly higher than the league average (.299 BABIP) in 2017 and if maintained, lofty enough to become the third-highest in major league history. And therein lies the rub: BABIP this high typically does not last. In fact, we haven’t seen a full-season BABIP this high by any hitter qualifying for the batting title since 1911, when Jackson and Ty Cobb did it.

Just two batters, with a minimum of 350 plate appearances, managed as high a BABIP as Judge during the first half of a season: Cobb (.430 in 1915) and David Wright (.426 in 2009). Both saw a BABIP decline in the second half.

Player Year 1st Half BABIP 2nd Half BABIP End of Season BABIP
Ty Cobb 1915 0.430 0.363 0.397
David Wright 2009 0.426 0.344 0.394
Aaron Judge 2017 0.426 ??? ???

It is also the reason Judge’s second-half projection is so pessimistic. Based on Judge’s batted ball rates and speed from this season, his expected BABIP in the first half should be closer to .354, which is slightly higher than his second-half projections (.333), leading to a .262 average with 17 home runs and just 1.9 wins above replacement, creating runs at a rate that is 31 percent higher than average for the remainder of 2017.

Still impressive, but end-of-season numbers that would drop him to the eighth best rookie season per fWAR and 24th based on weighted runs created rather than the best of all time.