It’s been the topic of discussion for numerous years.
According to the statistics and the players themselves, a good percentage of the sluggers who take part in the annual home run derby tend to see a major plunge in their numbers to begin the second half, with the majority of those poor stats holding at that subpar level for the remainder of the season.
It’s happened in the past to power hitters David Ortiz, Ryan Howard, Josh Hamilton, Chris Davis and many, many other sluggers who have taken part in the derby only to see their pre All-Star break numbers vastly overshadow the statistics they posted in the second half of the year. And once again, it’s happening this season.
How much of this apparent trend is actually a pattern and how much is due to a player’s career law of average just showing up (for example, a 30 home run player who hits 20 home runs before the All-star break only to fall into a “slump” and hit 10 after the break is still holding to their average) is vastly debated.
Some people claim that there is a major impact to a player’s swing after they do nothing but aim for the fences when crushing balls in the home run derby. For that very reason, Ortiz and Hamilton have declined any derby invitations they’ve received since their initial derby appearances, with the most recent example being Jose Abreu, who didn’t want to show off his power up at Target Field this year for fear that it would mess up his swing.
But that’s just one side of the coin.
On the other side, people seem to believe that the second half numbers a player produces after a derby are just a player returning to the previously mentioned law of averages — after all, every player goes through a slump at some point every season. However, now that two weeks have passed since the derby, with multiple players who were in the 2014 home run derby currently struggling, I’d have to go with the theory that a player’s swing is affected by the derby, at least in the short term.
Justin Morneau was a participant in this year’s derby, but he’s yet to play in any games since that point, so there are no numbers to go by, though he was batting .312 with 13 home runs and 60 runs driven in before the derby. Fellow derby and Rockies teammate, Troy Tulowitzki, is also currently injured, however he took part in two games before hitting the disabled list, recording no hits in 5 at-bats, after batting .345 with 21 homers and 52 RBI’s over the first half.
While there are no true numbers to look at for either Morneau or Tulowitzki, and thus no way to know how each player would be performing, a couple of injuries after the derby isn’t exactly a positive thing.
Of the players who aren’t on the disabled list at the moment, Brian Dozier has seen the biggest fall in numbers of them all. After getting off to a career season to get the year started, with 18 homers and 45 RBI’s, the lone hometown player to take part in the derby is now batting a mere .125 with two RBI’s on a single home run since the second half began. Also joining him with a .100’s batting average since the derby is Todd Frazier (batting .154), who has hit just one home run after slugging 19 throughout the first half.
Adam Jones and Giancarlo Stanton 
are also sharing in the same fate, with both batting in the .200’s since the All-Star break.
Jones posted a .301 batting average with 16 home runs and 54 RBI’s to begin the year, and despite having fallen a bit in batting average since, he’s launched 3 homers and amassed 10 RBI’s since the break — not jaw dropping, but also not terrible.
Stanton on the other hand is doing much worse, having slugged just two home runs since the derby — a derby he lost, even though he was the heavy favorite to win — despite hitting 21 before the All-Star break.
But as has held true throughout derby history, not all players are seeing a slump.
Although he hasn’t found his power swing since the derby, Yasiel Puig is still hitting for average, having batted .333 in the past couple of weeks. However, with no home runs and just two runs batted in, after blasting 12 before the break and driving in 52 runs, he’s still not the Puig everyone has come to know.
Jose Bautista has fared fairly well since the derby, batting .333 with 3 home runs and 7 RBI’s, after batting .292 with 17 homers and 54 RBI’s in the first half, which holds fairly steady with his average pace over his career. Hitting .324 since the derby, Josh Donaldson is also holding his own, having hit a couple of homers in the second half after batting .238 with 20 homers over the first portion of the season.
The player who seems to have experienced the least amount of problems with his swing is the winner of the derby, Yoenis Cespedes, who actually looks to have improved. After batting just .254 to begin the year, Cespedes is batting .324 over the course of nearly 40 at-bats since the derby (admittedly, a small sample size). In addition, Cespedes has slugged 3 homers and driven in 10 runs in this second half, however, seeing an increase in stats after winning the home run derby in 2013, it would seem that Yoenis Cespedes is the exception to the overall derby rule.
The Unbiased MLB Fan 