Bill Plaschke wrote a piece today entitled “For the Dodgers, Corey Seager in the home run derby could be a disaster.” It talks about the issues other Dodgers players have had after participating in the Home Run Derby, and expresses concern that Seager’s swing will be affected.
This is a bunch of bunk. Even Gonzalez, quoted in the piece, expresses a sentiment that swinging in the derby does not affect the future.
"“We do home run derby every day in batting practice and that doesn’t change our swings,” Gonzalez said. “Guys are always swinging for the fences and it’s fine.” Gonzalez said the problem with Home Run Derby isn’t the swings, it’s the stories like these that warn about the swings."
Players that hit lots of home runs tend to regress. Players that hit lots of home runs and have notable seasons get selected for the Home Run Derby. Back in 2010, this SABR paper looked at the issue from a variety of angles, and found no evidence of a curse.
It looked at splits for the same players in other seasons, and changes in OPS and home run rates.
Another way would be to look at players who hit a lot of home runs but did not participate in the Home Run Derby in the year in question, by choice or by not being selected. If there was a curse, we should see participants have a bigger dropoff.
I took all participants over the last 5 years, and included all that played at least 40 games in the second half of the season (using baseball-reference season split data). That left 38 participants (4 missed a large chunk of the second half). I then took the players who did not participate but had the most home runs at the break, and also played at least 40 games.
Here are the results:
HOME RUN DERBY PARTICIPANTS: home run every 4.5 games before ASG; home run every 5.9 games after ASG. Home run totals for second half 59.9% of first half.
HOME RUN HITTERS WHO DIDN’T PARTICIPATE: home run ever 3.8 games before ASG; home run every 5.1 games after ASG. Home run totals for second half 57.1% of first half.
The games played in the second half were nearly identical (2499 combined for Derby participants, 2523 for others).
Those who didn’t participate had a higher rate of home runs (because some participants were not among the league leaders at the break), but the dropoff from the first half to second half was nearly identical, and slightly more for those that didn’t participate. For every Joc Pederson, I could point to a case like Jose Abreu from 2014, who had 29 at the break but only hit 7 more in the last 63 games.