"Now you tell me." -- The proverbial famous last words said after finding out pertinent information when it's too late to use it to your advantage.
Unfortunately, when it comes to how the 2020 baseball will play in terms of power, we'll probably know 350 games into the season -- again, too late to incorporate into draft preparation.
However, it is possible to assemble a list of players who are most likely to be affected if the baseball reverts to 2018's traits.
Before delving into the methodology to unearth the players in danger of losing power, here's a brief explanation of how the aforementioned 350 games was determined. Below is a table showing monthly HR% (home run per plate appearance) from 2015 to '19.
Here are the differences between April and season-ending numbers:
For the past three seasons, the final HR% was about 0.2% higher than April's mark. While this isn't a lock, there's compelling evidence that April's HR% foretells how the season will play out. In fact, breaking April into 50-game increments, HR% stabilizes after 350 total games played, corresponding to the end of play on April 21.
Unless you have an extremely benevolent commissioner, willing to delay the draft until April 22, the season-ending power numbers will be unclear. We'll have a rough idea much earlier, but even that is too late to adjust player expectations.
Don't fret: The next best thing is to identify a subset of players with the greatest probability of reverting to warning track power if the drag in the ball increases. Not only does this avail a list of batters for whom you'll want to adjust expectations, it presents a buying opportunity for some hitters for whom other managers will anticipate to drop in power without doing the ensuing analysis.
Mike Podhorzer first presented this research on Fangraphs several years ago. There's a direct relationship between HR/FB (home run per fly ball) and average fly ball distance. A perfect relationship results in a correlation coefficient (R) of 1.00. Historically, R is at least 0.75, a very strong correlation.
Last April, after Rob Arthur published a study on Baseball Prospectus indicating that well-hit fly balls are traveling up to 10 feet further due to reduced drag, I identified a set of hitters meeting the following criteria:
Above 40 percent fly ball rate
Below 25 percent strikeout rate
Average 2018 fly ball distance between 315 and 329 feet
The average fly ball distance was determined to be the sweet spot where the added distance would yield proportionately more homers. A shorter distance wouldn't lead to as many homers, while longer ones were homers regardless. Of the 16 batters discussed, 12 indeed exhibited home run growth beyond the league average. Eight more missed the strikeout-rate cutoff, but five also surpassed the league-average gain in home runs.
Based on those encouraging results, along with the uncertainty of the 2020 ball, the follow-up study is unearthing hitters whose gain in power could be lost if their fly balls travel 10 feet shorter. A review of some of the batters' average exit velocity on fly balls will be included in the analysis. This goes together with fly ball distance, but there are some players with an average exit velocity on fly balls out of proportion to their overall average exit velocity, relative to the league. This will be most apropos when pointing out players likely to maintain their power gains even if the ball changes. For comparison purposes, the league-average exit velocity on fly balls was 92 mph.
Hitters likely to lose power
Anthony Rendon, Los Angeles Angels: Let's get the most controversial name out of the way first. For the record, Rendon was pegged as someone in line to benefit from the ball last season, and it came to fruition with a career 34 dingers. While a 335.4-foot average fly ball distance has a little wiggle room, the former Nationals star is moving to a park less forgiving to right-handed sluggers. His average exit velocity on fly balls increased only 1 mph to 93.5, so a drop in four-baggers is probable.
Gleyber Torres, New York Yankees: Torres is another risky top hitter, perhaps not worthy of his market rank. The underlying metrics are harbingers of a drop from last season's 38 homers, though the righty swinger is aided by opposite-field power in Yankee Stadium. A 326.3-foot average fly ball distance and 93.2 average exit velocity on fly balls just don't back threatening 40 homers.
Ketel Marte, Arizona Diamondbacks: Marte is on the upswing, so organic growth could help mitigate some decline, but unfortunately, his power spike wasn't strictly a result of skills growth, so expect Marte to give back some pop. His 326-foot average fly ball distance and 91.5 mph average fly ball exit velocity don't support 32 homers, and that's without considering a less flighty ball.
Marcus Semien, Oakland Athletics: Semien's numbers tracked almost identically to Marte's, so the conclusion is similar: a drop in home runs. Although Semien's average exit velocity was a tick higher than Marte's, he plays in a more cavernous venue. Both Semien and Marte are looking to fall from low 30s to mid-20s.
Jorge Polanco, Minnesota Twins: Polanco contributed a career-high 22 homers to the Twins' historic total. However, his average fly ball distance was just 319.9 feet, along with a below-average 91.5 mph average exit velocity on fly balls, both foretelling a drop in long balls.
Christian Vazquez, Boston Red Sox: There are signs Vazquez improved as a hitter, so the landing may be soft, but he'll have a hard time maintaining the power enjoyed last season. That said, he could make up for it in volume, playing more than the three out of five games he's seen the past few campaigns. Vazquez's average fly ball distance in 2019 was 323.9 feet, well within the range where losing 10 feet is most detrimental. Vazquez increased his average exit velocity on fly balls, but only to 92.2 mph, barely above league norm.
Yuli Gurriel, Houston Astros: Perhaps the least surprising name on this list, Gurriel takes advantage of the Crawford Boxes in Minute Maid Park. That said, a 319.1-foot average fly ball distance can't afford to be lessened with a different baseball. Turning 36 years old in June, Gurriel isn't likely to add any authority to a low 90.1 mph average exit velocity on fly balls.
Omar Narvaez, Milwaukee Brewers: Many expect Narvaez to build on last season's power output after moving to Miller Park from Safeco Field. More than likely, the more power-friendly venue masks a drop in long ball prowess. Last season, Narvaez's 312.9-foot average fly ball distance was the shortest of anyone swatting at least 20 out of the park.
Hitters likely to maintain power
Jorge Soler, Kansas City Royals: Soler truthers, take a bow. His home run total of 48 was fully backed by an impressive 352-foot average fly ball distance, the longest of anyone hitting at least 20 homers. Even a ball with more drag won't keep Soler from continuing to slug away.
Josh Bell, Pittsburgh Pirates: Bell's uneven first and second halves aside, the overall numbers portend a continued display of power. His 343.6-foot average fly ball distance can easily afford to lose some travel, as Bell's 95.8 mph average fly ball exit velocity suffices, even in power-suppressing PNC Park.
Gio Urshela, New York Yankees: There's no doubt Urshela benefited from the ball, but he also added 4 mph to his average exit velocity on fly balls. His average fly ball distance ballooned to 337.4 feet, so even if he loses some distance, Urshela is in good shape to maintain the power spike others will assume will wane.
Roberto Perez, Cleveland Indians: Coming into 2019, Perez had 21 career homers in 963 plate appearances. Last season, he hit 24 long balls in 449 trips to the plate. His average fly ball distance was a whopping 344.2 feet, easily long enough to withstand losing a few feet without dropping too much power. In addition, Perez upped his average exit velocity on fly balls to 96 mph, well above league norm.
Danny Santana, Texas Rangers: Many are befuddled by Santana's 28-homer outburst last season, but they shouldn't be. He has actually underproduced his average fly ball distance and exit velocity the past couple of seasons. Last season, he received the commensurate results -- although it should be pointed out that the new Globe Life Field is likely to reduce homers compared to Globe Life Park.
Mitch Garver, Minnesota Twins: Granted, it will be a chore for Garver to match last season's exploits, but the breakout was real, so the follow-up campaign could exceed expectations of those deeming last year a fluke. Driving fly balls with a hefty 96.8 mph average exit velocity isn't done by accident.
Brian Anderson, Miami Marlins: Anderson has two things going for him. Not only does the right-handed batter have opposite-field power in a venue where the right-field fences are coming in, he also added 3 mph to his average exit velocity on fly balls last season, posting an above-league-norm 94.1 mark.