At some point this year you have probably noticed that there were a lot of home runs hit. It might have been when Mike Moustakas finally broke the Royals franchise record for home runs:
Maybe it was when Giancarlo Stanton challenged the 60 home run plateau:
Could it have been when Cody Bellinger broke the National League rookie home run record:
Perhaps it was when Aaron Judge shattered the league-wide rookie home run record with his fourth bomb in two days:
If none of those then it was definitely when Alex Gordon finished off the old league-wide record for home runs in a year with nearly two weeks left to play:
Whenever it was that you noticed you could hardly have missed it. It seems to be taken for granted that the baseball has been “juiced”. Though, of course, not everyone agrees. Still, everyone seems willing to agree that if the baseballs were juiced it would be because Commissioner Rob Manfred/the owners/baseball/somebody wanted more offense to make the game more exciting and thereby draw more fans and talent to the sport.
The thing is if final goal was more overall offense the increased home runs didn’t actually accomplish that. About 400 more home runs have been hit this year than any year in MLB’s history, including the “Steroid Era” of the late ‘90s and early ‘00s and yet the runs scored this season rank only eleventh all-time - nearly 2,500 runs fewer than the number scored in the year 2000, the previous home run record holding season and still leader in runs scored. Home runs are the easiest and most obvious way to score runs, so how can there be so many more home runs but also so many fewer runs scored?
The most obvious difference between the 2000 league and the 2017 league is the number of strikeouts. Strikeouts have reached a new high this season, for the tenth consecutive season. However, anyone who has watched Salvador Perez or Albert Pujols pound a grounder directly to the shortstop can tell you that a strikeout isn’t always the worst outcome. Baseball in 2017 featured about 100 fewer ground ball double plays than 2000. Fewer eliminated runners and more home runs still seems like it should equal more runs.
Unfortunately not all of the batted ball data can be compared between the two leagues because FanGraphs only goes back to 2002. Baseball Reference doesn’t appear to track velocities and only has batted ball location data through 2016 right now. Still we can tell a little bit from the data that we do have. 2017 features the most hard hit balls out of any of the recorded years, on FanGraphs which makes sense. It also features the second-most soft-hit balls and the least medium-hit balls.
A big part of the “flyball revolution” is the realization that going boom-or-bust can be a productive plan at the plate. Speaking of the flyball revolution, the 2017 season only comes in 8th out of 16 seasons from 2002-2017 in flyball percentage. Given that line drives are still sought after as part of this revolution you might expect them to be up, at least, but this season was only 9th over that time. If you compare the percentages between 2017 on FanGraphs and 2000 on Baseball Reference you do see that there are more flyballs now than then, but so many fewer line drives that the groundball percentage is actually higher now, as well - a net loss for the revolution.
Remember that bit about batters being more willing to go boom or bust? The place that’s really showing up is in the batting averages - down a whopping 15 points from 2000 - as well as on-base percentages. Despite the fact that every team should now be willing to admit that a walk is a terrific outcome for an offense - especially when there are so many more home runs than before to score those walks - and that they should be seeking out players who will get those walks, on-base percentage is down a whopping 20 points from 2000.
Slugging percentage, for that matter, is also down 10 points despite the drastic increase in home runs. Home runs are up, but singles, doubles, triples, and walks are all down. All in all there were about 3,000 fewer hits in baseball this year, compared to the year 2000. This ties neatly back into the strikeout surge from earlier. BABIPs between 2000 and 2017 are roughly the same, so the relative lack of balls in play means fewer runners.
This all has led to about 350 more solo home runs in 2017 than 2000. There was a 7% increase in total home runs, but an 11% increase in solo home runs. There were actually fewer grand slams and three-run dingers. Two-run blasts increased, but at a lesser rate than the home-runs overall so they still make up a smaller percentage of the overall total of home runs hit.
How can a season have so many more home runs but so many fewer runs? When almost all of the extra bombs are solo shots. The flyball revolution has drastically increased individual performance for an impressive number of players, but it’s actually helped bring total offense down.
Home runs are exciting so adding those is good, but strikeouts and easy flyouts are generally considered to be less so and they all come as a package deal. Mostly what it appears to be accomplishing is converting singles into home runs and outs. If Manfred and others want to increase offense in baseball they may need to take steps more drastic than juicing baseballs. They might have to figure out to convince major league baseball players to change their approach at the plate.