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We Came Up With A New Way To Determine Baseball’s Top Power-Speed Guy

Baseball has always prized players who can hit the ball a country mile or run like the wind. And when the same player can do both of those things, he becomes the stuff of legends — like when Willie Mays hit 36 home runs and swiped 40 bases in 1956, or when Jose Canseco inaugurated the 40-40 club in 1988.

So, who is today’s version of Mays or Canseco — the best mix of both power and speed? There is the traditional way of measuring it, but we can do a better job using MLB’s new Statcast metrics, which track the exact velocity of a ball off a player’s bat and the speed of his body around the basepaths.

Bill James originally captured a player’s combination of slugging and running by inventing a statistic called the Power/Speed Number, introduced in his 1980 “Baseball Abstract.” The formula is simply the harmonic mean of home runs and stolen bases: two times home runs times stolen bases, divided by the sum of home runs and stolen bases. “It is so crafted that a player who does well in both home runs and stolen bases will rate high,” James wrote, “and his rating is determined by the balance of the two as well as by the total.”

According to this basic accounting system, the best combo of power and speed in any single season belonged to Alex Rodriguez in 1998, when he hit 42 home runs and stole 46 bases — just the third of four 40/40 seasons in MLB history.1 The best Power/Speed Number last season belonged to Jose Ramirez of the Cleveland Indians, who hit 39 home runs and stole 34 bases; that season is tied for 31st all-time in James’s metric.

For this season, White Sox shortstop Tim Anderson led baseball on April 18 with a 4.8 Power/Speed Number (four homers and six steals) — though that’s not really comparable to full-season numbers because the metric is a mean of two cumulative stats, meaning that it grows as the season goes on.2 A better way to get numbers that resemble full-season stats is to combine actual results from the first few weeks of the season with rest-of-season projected homers and steals from FanGraphs’ depth charts. After we did that, the top projected Power/Speed player of 2019 was Adalberto Mondesi of the blazing-fast Kansas City Royals — he’s on pace for 48 stolen bases and 22 home runs.

##### Baseball’s best at combining homers and steals

The top players in 2018, 2019* and all-time according to Bill James’s Power/Speed Number (PSN)

Player PSN Player PSN Player Year PSN
Jose Ramirez 36.3 A. Mondesi 30.2 Alex Rodriguez 1998 43.9
Trevor Story 31.2 Mike Trout 27.8 A. Soriano 2006 43.4
Mookie Betts 31.0 Ronald Acuna 27.4 Eric Davis 1987 42.5
F. Lindor 30.2 Trevor Story 27.4 R. Henderson 1986 42.4
Mike Trout 29.7 Jose Ramirez 26.9 Barry Bonds 1996 41.0
C. Yelich 27.3 Mookie Betts 24.8 Jose Canseco 1988 41.0
Trea Turner 26.4 C. Yelich 24.0 Bobby Bonds 1973 40.9
Javier Baez 26.0 Jonathan Villar 24.0 Barry Bonds 1990 40.4
Starling Marte 24.9 Tim Anderson 24.0 Eric Davis 1986 40.4
Tim Anderson 22.6 Javier Baez 23.8 A. Soriano 2002 40.0

* Projected full-season Power/Speed Numbers (as of April 18, 2019) according to FanGraphs’ depth charts

Sources: Baseball-Reference.com, FanGraphs

Mondesi certainly is fast — he ranks second in all of baseball (behind Minnesota’s Byron Buxton) in Statcast’s sprint speed metric, which tracks a player’s velocity on running plays in which he is theoretically hustling. His pop is also impressive for a speedster. If Mondesi were to hit his projections, he would be in great company: The 40/40 club’s lesser cousin, in which a player has 20 homers and 40 steals, has been done only 50 times in history and not at all since 2013. But according to Statcast, the average exit velocity of Mondesi’s batted balls is 88.9 miles per hour, which puts him in the bottom half of all qualified hitters.3

Homers and steals are proxies for power and speed, but they’re imperfect ones. If we use Statcast’s rankings as the basis for a new conception of James’s old Power/Speed Number — measuring power with exit velocity and speed with sprint velocity — it turns out that there are hitters who do an even better job than Mondesi of combining these two facets of the game.

I took every player who had at least one batted-ball event and one running event in every 1.8 games through April 184 and calculated his percentile rank in each category. Then, like with James’s original metric, I took the harmonic mean of those two values for a combined score that rewards high rankings in both power and speed.

Last season’s top power-speed player was — who else? — Mike Trout of the Los Angeles Angels, who ranked 31st in exit velocity and 17th in sprint speed.

Of course, Trout also ranked fifth on our original Power/Speed leaderboard … but where is Ramirez in this updated version? Surprisingly, the Indians’ MVP candidate was only 85th in the new ranking, despite leading MLB in James’s metric. He had a lot more steals and homers than we would have expected from his raw physical tools. As my colleague Travis Sawchik documented last season, Ramirez made up for a lack of pure power with a concerted focus on lifting the ball in the air to his pull side, particularly to right field as a lefty hitter. (Ramirez hits from both sides of the plate.) He was also smart about picking his spots as a base-stealer, ranking seventh in stolen-base percentage with an 85 percent success rate.

But this version of the Power/Speed Number is more about measuring the skills that help lead to home runs and steals — rather than the homers and steals themselves — so players like Ramirez are out in favor of those like the Braves’ great young left fielder Ronald Acuña Jr., who consistently hits rockets off the bat and is one of the fastest runners in the sport.

##### Who combines the best Statcast power and speed metrics?

2018 and 2019 MLB leaders in percentile ranks for both power (by average exit velocity) and speed (by average sprint speed)

Player power speed Mean* Player power speed Mean*
1 M. Trout 91 95 92.9 C. Bellinger 99 95 96.6
2 R. Acuna 88 98 92.5 B. Buxton 91 100 95.5
3 T. Story 88 98 92.5 R. Acuña 88 98 92.3
4 C. Yelich 95 88 91.4 J. Alfaro 93 90 91.4
5 T. Pham 97 85 90.5 M. Trout 91 90 90.4
6 T. Hernández 94 85 88.9 N. Goodrum 90 90 89.9
7 S. Ohtani 97 81 88.1 H. Pence 91 85 87.8
8 A. Altherr 84 92 87.9 J. Báez 92 84 87.4
9 Y. Moncada 86 90 87.6 T. Story 78 98 86.9
10 M. Chapman 98 79 87.2 J. Martin 89 84 86.2

* Harmonic mean of the percentile ranks for exit velocity and sprint speed

2019 numbers through April 18

Source: Baseball Savant

Acuña was second last year and is third so far in 2019, coming up on the heels of Buxton (who might be the anti-Ramirez — he has one of the league’s highest average exit velocities despite zero home runs this season or last). But neither player ranks No. 1. That honor belongs to Cody Bellinger of the Los Angeles Dodgers.

The power part isn’t shocking. Bellinger already has 11 home runs this season, second in the majors behind Christian Yelich. He’s leading the majors in an absurd array of stats, including wins above replacement, batting average, slugging percentage, hits, runs, total bases and on-base plus slugging (OPS). Through April 18, Bellinger ranked sixth in average exit velocity at 95.9 miles per hour.

But speed? According to FanGraphs, the 6-foot-4, 210-pound Bellinger was rated by scouts as a “45” in the category back in 2017, with average at 50. And yet, Bellinger was up to 16th in Statcast sprint speed at 29.0 feet per second, tied with Kansas City speed-merchant Billy Hamilton (!). In just the first three weeks of the season, Bellinger already had 27 of what Statcast classifies as “competitive runs,” which contribute to his average, so it’s unlikely that the radar-trackers merely picked up a few aberrant readings. That’s particularly the case since Bellinger also ranked 35th overall in sprint speed last season, with a 28.8 feet-per-second average over 224 competitive runs.

Interestingly, the power component might be the more likely area of regression for Bellinger. Although he exploded for 39 home runs in his first 132 major league games in 2017, his power dipped last season, with an average exit velocity that didn’t rank among the top quarter of MLB hitters. He appears to have made adjustments after a classic sophomore-slump campaign, blistering the ball early this season, but Bellinger has the longer track record of having an elite sprint speed than having elite batted-ball metrics.

Bellinger is simply surprisingly fast in terms of in-game speed. And that works in concert with his crazy mashing to make him MLB’s best power-speed player in the early part of this season.

Check out our latest MLB predictions.

## Footnotes

1. The most recent was Alfonso Soriano’s in 2006.

2. The career leader in Power/Speed is Barry Bonds with a mark of 613.9 — gargantuan relative to the single-season record of 43.9.

3. Minimum 25 batted-ball events.

4. Which worked out to about 10 so far this season and about 90 over a full season.

Neil Paine was the acting sports editor at FiveThirtyEight.