An unusual home run explosion
Something had changed in 2015, but what? As the 2016 season kicks off, a look at the perfect storm that combined to create Major League Baseball’s biggest home-run surge since the steroid era
MAJOR LEAGUE BASEBALL was in a home run recession. Entering the 2015 season, leaguewide home run totals had been dropping precipitously, from 4,934 in 2012 to a 20-year low of 4,186 in 2014.
A variety of factors explained the plunge in power. Even beyond stricter drug-testing guidelines weeding out the performance-enhancing-drug-fuelled sluggers of the late 1990s and early 2000s, new approaches and strategies were hindering hitters. Higher velocities from pitchers and an ever-expanding strike zone put strikeouts at an all-time high. Managers began treating pitchers as sprinters rather than long-distance runners, calling more frequently to the bullpen for fresher arms with better pitch-placement at crucial times, while front offices focused on stockpiling hard-throwing relievers.
The downward trend in offence was easily understandable. And that’s what makes the 2015 season so mysterious.
Last season, MLB’s home run total jumped by 723, or 17.3 per cent, a spike not seen since 1996 when homers boomed by 21.6 per cent in the nascent days of MLB’s so-called steroid era. (The Toronto Blue Jays hit the most home runs in baseball last year, with 232, or an average of 1.43 per game).
Since 1970, baseball has only witnessed six seasons in which the home run total increased by 700 or more. Five of them are explainable by events in and around the game.
The first such spike in 1977 coincided with MLB’s switch from balls produced by Spalding to a new version made by Rawlings, the same manufacturer used today. Hitters launched 1,409 more home runs that season. In 1982, the second 700plus home run spike, baseball was returning from a players strike that cost the league 38 per cent of its season in 1981. The 1994 strike produced a similar result, with a 775-homer increase in 1995. Those seasons were bookended by home run explosions in 1993 (992) and 1996 (881) that correlate with the start of widespread PED use in the game.
Then there is 2015, when baseball’s offensive downturn was reversed in remarkable fashion. The odds of such a development are so slim, they were almost incalculable to Robert Vanderbei, a math professor at Princeton University.
Washington Nationals ace Max Scherzer similarly lacked an immediate answer. He wondered how many ballparks had moved in fences. Then he wondered if the ball had changed, noting he would not necessarily be able to feel all alterations while throwing it.
“Every year parks bring their fences in, don’t they?” said Shawn Kelley, who pitched last year with the San Diego Padres.
The Padres, along with the New York Mets, did move in their outfield walls last season at their home, Petco Park. “It used to be the hardest one to hit in and last year it wasn’t,” Kelley said. Changes to stadium dimensions did play a role, but the alterations in San Diego and Queens only upped the totals for the Padres’ and Mets’ home parks by a combined 99 home runs from 2014 to last season.
Other theories included climate change, improved scouting, even a conspiratorial suggestion the ball itself may be livelier. But a closer examination yields no single, clear cause to explain one of the biggest offensive outbursts in baseball history.
WHAT IT WASN’T
Some offered explanations can be eliminated, however. It’s true 2015 was the warmest year on record, and it’s also true baseballs fly farther in hotter temperatures. Alan Nathan, a professor emeritus of physics at the University of Illinois, found an increase of average temperature by one degree Fahrenheit would result in an increase in home runs by about 0.6 per cent.
Per baseball-reference.com, average game temperatures during night games increased from 73.0 to 73.7 degrees from 2014 to 2015, and from 71.6 to 73.5 during day games. But to fully account for the 17.3 per cent spike we observed last season, temperatures would need to jump from those averages around 73 degrees all the way to 361 degrees Fahrenheit across all games. Equipment changes can also be ruled out. While Barry Bonds may have popularized using maple bats, over the then-more common ash, when he set the single-season home run record in 2001, the lumber is a nonfactor.
“If a baseball player thinks they can hit better with a maple bat, maybe they can hit better,” explained James Sherwood, director of the University of Massachusetts-Lowell Baseball Research Center. “But from a scientific perspective, there is no difference.”
One MLB scout with over 30 years’ experience suggested the possibility of a livelier ball, the theory also put forward by Scherzer.
Changes to the ball could explain the jump. In 1974, when Spalding was still the manufacturer on record, the ball’s outer coating went from horsehide to cowhide, and home run production dropped nearly 15 per cent from the year before. Rawlings, the current manufacturer of MLB baseballs, took over from Spalding in 1977, and home runs jumped up 63 per cent in a single season.
Changes — no matter how slight — can have immediate effects on the league’s home run rate. But not in this case, according to Rawlings.
“Major League Baseball audits our plant at least once a year and is completely satisfied with the ball we produce,” said Mike Thompson, the executive vice-president of marketing for Rawlings. “There is ongoing testing all year long just to make sure the consistency meets Major League Baseball’s needs.”
In 2000, Major League Baseball and Rawlings funded a study by Sherwood at the University of Massachusetts-Lowell Baseball Research Center to study the baseballs being used. Sherwood, who continues to examine baseballs for MLB today, found “no significant performance differences and verified that the baseballs used in Major League games meet performance specifications.”
SO, WAS IT THE PLAYERS?
One possible explanation stems from the significant influx of young talent into the game. Last season, baseball debuted arguably its best-ever rookie class, one that included Chicago Cubs sluggers Kris Bryant (26 home runs) and Kyle Schwarber (16), Los Angeles Dodgers outfielder Joc Pederson (26), Houston Astros shortstop Carlos Correa (22) and Twins infielder Miguel Sano (18).
In total, last season’s rookies blasted 714 home runs, an MLB record. But that total still doesn’t account for the entirety of the spike. There are rookies every season. When you adjust for the home runs hit by rookies in 2014, even this record total accounts for only 360 of the extra 723 home runs. Breaking down the league by age, we see an even more notable spike elsewhere. Older hitters saw a surprising rise in home runs as well.
The home run totals for players 31 and older have steadily trended downward since the end of the steroid era, considered to be 2006 with the introduction of MLB’s drug testing reforms. In 2015, however, those veterans hit 320 more home runs than 2014 while posting the highest yearover-year increase in home runs per plate appearance for that demographic since the 1993 (plus-24 per cent), 1994 (plus-18 per cent) and 1996 (plus-22 per cent) seasons.
The findings of MLB aging curve studies are consistent: players get worse as they get older. In a study by Jeff Zimmerman of FanGraphs, players from 1995 to 2005 showed a steady increase in home run production before tapering off after their 30th birthday. From 2006 to 2013, the curve changed to a consistent decline that began closer to age 25. This wasn’t the case last season, when the game’s elder statesmen were turning back the clock. The poster child, or geezer, for this group is the New York Yankees’ Alex Rodriguez, who turned 40 last season but hit 33 home runs (5.3 per cent of his plate appearances) after missing the entire 2014 season for violating the league’s performance enhancing drugs policy. Age 31-plus players Joe Mauer, Ben Zobrist, Robinson Cano, ShinSoo Choo, Torii Hunter, Ryan Howard and Albert Pujols all saw year-over-year improvement in terms of home runs per plate appearance. Pujols, at 35 years old, hit 40 home runs in 2015, his highest total since 2010. Nelson Cruz, the league’s sole member of the 40-home run club in 2014, hit 44 home runs in 2015 despite making less contact, pulling the ball less and hitting fewer fly balls. He turned 35 in April.
Those final notes about Cruz’s season add another leaguewide layer to the mystery, regardless of age: While more balls are leaving the yard, players aren’t making more contact.
Perhaps one explanation is the approach of modern hitters. In part fuelled by baseball’s analytic revolution, teams have de-emphasized the negative impact of a strikeout, encouraging hitters to swing hard and for power.
“Organizations are valuing guys with a specific type of swing and approach,” the executive said in a phone interview. “That’s why when solid contact is made, there is higher bat speed and higher exit velocity. That’s why you are seeing a home run-to-fly ball ratio that is a little more significant.”
Combine this approach with better information and hitters are better prepared than ever to smash a home run.
“I’d put it [the home run spike] more on the advancements we are making,” the executive said. “Teams are smarter, more information is available and there are philosophical shifts happening all over baseball. We have the tools to analyze everything now and we are valuing things differently.”
Harder swings combined with better insights regarding pitch placement and type would definitely impact home run rates. “It’s a mindset,” said one MLB scout. “Guys are taking more pitches, getting themselves into counts where they are trying to drive the ball. There is a concerted effort on the hitter’s part to do that.”
But why is the home run spike only coming now when the advancements in scouting reports and the emphasis on power over contact have been in the game for years?
“Guys that don’t have those specific characteristics are being filtered out of the game,” the executive said. “And the cream is rising to the top.”
MAYBE IT’S A LITTLE BIT OF EVERYTHING?
While no single factor provides a clearcut answer for the home run surge, the best explanation may be a perfect storm. Combine the increases due to park effects, warmer temperatures, a generational rookie class, better informed hitters who are swinging harder than ever and the paring down of the game’s elder demographic to its best power hitters and it’s reasonable to believe that combination could produce the 723-homer spike in 2015. But perhaps there is one more cause. The biggest culprit might be expectations.
After a nosedive in the home run department in 2014, we would expect some sort of progression back to “normal” levels in 2015. In the nine seasons since the end of the steroid era in 2006 to 2014, major-leaguers have averaged 4,801 home runs per season. In other words, if 2014 hadn’t been such an abysmal year and was instead an average year for long balls, the 2015 uptick would have been just 108, a mere blip. Though it may not satisfy conspiracy theorists, a simple progression back to the post-PED era mean, combined with the variety of other factors above, might just be the best theory to explain the single biggest home run spike since steroids swept through clubhouses in the 1990s.
THE TORONTO BLUE JAYS HIT THE MOST HOME RUNS IN BASEBALL LAST YEAR, WITH 232, OR AN AVERAGE OF 1.43 PER GAME