http://www.fangraphs.com/blogs/the-home-run-derby-curse/
https://www.beyondtheboxscore.com/2017/7/5/15919218/home-run-derby-curse-2017
First thing is first: the players that are selected to the Home Run Derby are always those who have hit a lot of homers in the first half of the season. That number is backed up by the fact that just one (let’s bold and italicize that) of the 80 data points posted a first half HR/FB rate of below the 10.1 percent median. That was 2014 Yoenis Cespedes, who fell just 0.1 percentage points shy with a 10.0 percent HR/FB rate after hitting 14 home runs in the first half.
That makes 79 of 80 — or 98.8 percent — of Derby participants over the last 10 years already “lucky” from their first half numbers by what would be considered an inflation fly balls to home run rate.
What’s more is that these players weren’t just lucky in the first half; they were extremely lucky. An outrageous 41 of the 80 participants — just over half — posted first half HR/FB rates of above 20 (!!!) percent. For an outrageous comparison, in 2014, just six of 146 qualified hitters (4.1 percent) kept their HR/FB rate above 20 percent for the entire season. In a normal year, we see between 10-15 hitters do this. Regardless, it shows how rare it is to have this high of a HR/FB rate.
That’s why it all has to come crashing back down to Earth.