Major League Baseball publicly released a trove of bat-tracking data today that offers fascinating insights into what makes the best hitters good — and the worst bad. With everything from bat speed to swing length to sweet spot contact measured, it will have a similarly profound effect on hitters that ball-tracking data had on pitchers.

Using the Hawk-Eye tracking system that positions 12 cameras around every major league stadium — including five running at 300 frames per second — MLB has spent more than two years refining the bat-tracking model before releasing it on its Statcast platform. In measuring using the sweet spot about 6 inches below the head of the bat, every swing of every hitter is documented through objective data and ready for analysis.

Here are the basics. The average major league swing is 71.5 mph. The average length of the bat’s path on a swing, start to finish, is 7.3 feet. Hitters square up the ball on one-third of batted balls. The fastest swings typically belong to the most productive players — but not always. The average bat speed for the best hitter in the major leagues this season, Shohei Ohtani: 75.4 mph. The average bat speed for the worst hitter in the major leagues this season, Javier Baez: 75.4 mph.

Just as the advent of the pitch-tracking era prompted changes in training methods to juice velocity and spin, the ability to measure bat speed and paths will likewise change the approaches of hitters in future years. For now, though, in this nascent stage, the data is pure and unadulterated. And it tells us that when it comes to bat speed, there is one man, and then there is everyone else.

The king of bat speed

When Statcast debuted in 2015 and exit velocity jumped to the fore of baseball lexicon, Giancarlo Stanton, then with the Miami Marlins, topped almost every leaderboard. That season, there were 12 balls hit at least 117 mph. One from Mike Trout, one from Nelson Cruz, one from Carlos Gonzalez and nine from Stanton.

The now-New York Yankees slugger’s bat-speed numbers are similarly gaudy. Stanton’s swing, on average, comes in around 80.6 mph — nearly 3 mph higher than the second-fastest swinger, Pittsburgh Pirates shortstop Oneil Cruz. It’s also consistently fast. Statcast is characterizing all swings over 75 mph as “fast.” Just over 22% of swings reach the 75 mph threshold. Stanton is at 98.0%, nearly 25% ahead of the next best, the Philadelphia Phillies’ Kyle Schwarber, who swings 75-plus mph 73.9% of the time.

Stanton is also near the top of another category: swing length, where he’s second behind Baez. Height often influences swing length, and at 6-foot-6, it’s no surprise to see Stanton’s swing covering 8.4 feet.

Of course, as Stanton’s struggles in recent years have taught, exit velocity — and now, bat speed — do not by themselves make for a great hitter. Stanton has the single hardest-hit ball in MLB this season at 119.9 mph and the highest average exit velocity on his hardest-hit balls, but he has been only a slightly-above-league-average hitter, batting .230/.283/.452.

The lesson: You can have the fastest swing around, but by no means does it guarantee success.

The anti-Stanton

On the other end of the spectrum is San Diego Padres craftsman Luis Arraez, who can add a new title to his two batting crowns: the slowest bat in baseball. Arráez’s bat speed of 62.4 mph lags 2 mph behind the second-most languid, Cleveland Guardians outfielder Steven Kwan, and the two are perhaps the best examples of what players without elite bat speed can do to continue thriving in the big leagues.

Arráez and Kwan are part of the cohort of controlled, short swings that get squared up with a phenomenal amount of regularity. Arráez’s swing is just 5.9 feet and Kwan’s 6.4. In the group of sub-68-mph bat speed and sub-6.4-foot swing length are Milwaukee Brewers second baseman Brice Turang (128 OPS+), Yankees outfielder Alex Verdugo (107) and Toronto Blue Jays DH Justin Turner (111), all of whom are productive offensive players.

One might suggest it’s in spite of their swings, but perhaps it’s better to start treating it like it’s because of them. Arráez leads MLB by squaring up the ball on 43.9% of his swings. To determine whether a pitch has been squared up, the system takes two variables — bat speed and pitch speed — and determines the maximum exit velocity. Then it takes the actual EV on a batted ball and compares it to the peak. If it’s at least 80% of the top-end number, it is deemed to be squared up, because only balls that hit the bat’s sweet spot can produce 80%-plus velocities.

When hitters square up a ball, they bat .372 and slug .659. When they don’t, they hit .127 and slug .144. In other words, even if neither possesses much power, appreciate Arráez, Kwan and others for what they are: masters of the art of hitting.

The perfect marriage of bat speed and precision

Take Stanton, put him into one of those mash-up machines with Arráez, and what do you get?

Juan Soto. Just consider:

• At 76.1 mph, the Yankees right fielder has the 10^th-highest bat speed among the 221 qualified players.

• He swings 75-plus mph 66% of the time, ranking seventh.

• He has squared up 83 balls, the fourth most in MLB, and does so at a 48.3% rate, which is second.

• He is second in blasts, a metric that adds an element of bat speed to a player’s squared-up rate, with 49. The top 10 players in blasts are a “who’s who” of great hitters: Jose Ramirez, Julio Rodriguez, Aaron Judge, Yandy Diaz, Gunnar Henderson, Salvador Perez, Bobby Witt Jr., Ohtani, Soto and a surprising No. 1 whom we’ll introduce next.

A swing length of 7.3 feet is the only place where Soto is average. He’s not like Corey Seager, Freddie Freeman and Wyatt Langford, who generate excellent bat speed with short swings. Nor is he like the majority of players who join him near the top of the bat-speed list and generate it using long swings.

No, Soto is just spectacular at what he does. And his outlier status in bat-tracking data validates his place there with production, too.

The best hitter in baseball nobody knows

He has more blasts than Soto and Ohtani.

Only four players have squared up more balls than him, and each is a multitime All-Star.

He doesn’t even swing, on average, as hard as his brother. But that doesn’t matter, because William Contreras — the Brewers’ catcher, younger sibling of St. Louis Cardinals catcher Willson Contreras — does plenty of damage with a 74.2 mph effort. Not only is the 26-year-old Contreras atop the list of blasts, it’s not particularly close: His 58 are ahead of Soto’s 50 and Ohtani’s 46, and his big league-best blast rate of 34.5% is 2½ times the major league average of 13.7%.

The reason for Contreras’ success is clear: He swings hard, hits the ball very hard and doesn’t strike out much (sub-20% punchout rate on the season). It’s an exceptional combination of skills, and to have maintained this offensive output playing every Brewers game, not to mention 33 of 40 at catcher, is MVP-caliber work.

Others this season whose bat skills deserve credit:

Whose profiles are alarming?

While MLB attempted to start tracking swings using Statcast in a limited number of stadiums during the 2022 season, the league only felt confident enough this year to release the full set of numbers. Thus, it’s impossible to know for certain whose swing has gotten faster or slower in recent years.

Here are five players whose swing metrics over the season’s first seven weeks are cause for concern.

Javier Báez, SS, Detroit Tigers: Never has bat speed been a question for Báez, and this season reinforced that. The issue — or one of the issues — is that he lugs his bat through the zone longer than anyone, Stanton included. Baez’s 8.7-foot-long bat path simply doesn’t generate the hard contact it once did, and his .172/.208/.233 line reflects that.

Nolan Arenado, 3B, St. Louis Cardinals: Right behind Baez and Stanton in swing length is the 33-year-old Arenado. Long swings can be a good thing — Michael Harris II, Aaron Judge, Willy Adames, Rhys Hoskins and Adolis Garcia all rank in the top 10 — but they’re tough on a pull-heavy hitter with well-below-average bat speed. Arenado has clocked in at 69.5 mph this season, and while he’s been an average hitter in a down offensive environment, only a few others (Isaac Paredes, Jose Altuve) have found success with long swings and slower bats. All three have low blast rates, which is worth keeping an eye on.

Vladimir Guerrero Jr., 1B, Toronto Blue Jays: The 25-year-old has the makings of a good hitter. An average bat speed of 75.6 mph (14th in MLB) and 34 blasts (22nd) portend well. The issue? Guerrero is squaring up the ball at an anemic rate: just 21% of swings and 26.9% of the time on contact. The blasts show that when Vlad does hit the sweet spot, he does significant damage. He just hits the weak part of the bat far too often.

Jorge Soler, DH, San Francisco Giants: As bad as Guerrero has been at squaring up the ball, Soler is markedly worse. His bad speed is the same as Vlad’s at 75.6 mph, but he has the third-lowest squared-up rate on contact. The blasts are even worse: Soler has been the only player in baseball who swings harder than 73.2 mph and can’t muster even a 10% blast rate. Perhaps the right shoulder strain that forced him to the IL a week ago was the culprit? No longer is that a question left to speculation. The data upon Soler’s return will answer it.

Brett Baty, 3B, New York Mets: At the bottom of the list is Baty, the clearest example of the anomaly that is high bat speed, weak contact. While Baty doesn’t swing as hard as Soler or Guerrero, his 73.2-mph swing is certainly above average. His MLB-worst 18.0% squared-up rate on contact, on the other hand, is not. Getting out-blasted by Arráez when swinging 11 mph harder than him is a difficult thing to do.