Breaking down the Rays' bat-tracking leaders

This story was excerpted from Adam Berry’s Rays Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

BOSTON -- If you’ve watched the Rays over the past few years, it probably doesn’t come as a surprise to read that Randy Arozarena swings hard. Or that Yandy Díaz squares up a lot of pitches. Or that Isaac Paredes does things a little differently than most other hitters who produce impressive numbers like his.

Now, though, we can see how hard Arozarena swings. How often Díaz squares up the ball compared to his peers. And how Paredes gets the most out of his swing with his disciplined approach.

Teams like the Rays have known this stuff for a while, of course. But thanks to the high frame-rate Hawk-Eye cameras in each of the 30 Major League ballparks, we can track the speed of the bat, the length of a swing and the path it takes toward the ball. And now, for the first time, we have publicly accessible data that can quantify so much about hitters’ swings.

MLB.com’s Mike Petriello expertly explains what it means and why it matters in this story. You can see and sift through the data yourself on Baseball Savant. As we continue to learn more about Statcast’s new bat-tracking data and how to use it, let’s look at a few things it shows us about the Rays’ hitters this season.

Bat speed: This isn’t everything, in much the same way that velocity isn’t the only measurement that matters when evaluating pitchers’ fastballs. But it is important to generate power, and the numbers bear that out.

Of the eight Rays who qualify for Statcast’s leaderboard, Arozarena has the highest average bat speed, at 72.7 mph entering play on Friday. Díaz ranks second (72.5 mph) followed by Jose Siri (72.3), and everyone else ranks below the Major League average of 72 mph. Paredes (67.3 mph) has the slowest average bat speed among qualified Rays, behind Richie Palacios (69.1) and José Caballero (69.9).

Fast-swing rate: As Petriello wrote, “Most swings aren’t fast swings.” In fact, only about 23% of swings are, when you classify a “fast swing” as one of 75 mph or higher. Bat control specialists like Luis Arraez and Steven Kwan don’t swing fast. Only 3.4% of Paredes’ swings are fast, the lowest rate on the Rays.

The Rays with the highest fast-swing rates are Arozarena (36.4%), Díaz (28.1), Harold Ramírez (27.4) and Siri (22.8).

Swing length: Not all swings are created equal. A long swing typically generates more power with more swing-and-miss. Shorter swings are more direct, creating more contact with less impact. Players tweak the length of their swings depending on how they’re feeling, who they’re facing, the count, what they’re trying to do and so on.

Paredes has the Rays’ longest swing on average, at 8 feet, followed by Siri at 7.7. It’s worth noting there’s a lot of variance in Paredes’ swings, as he has the team’s longest recorded swing of the season (9 feet on an April 14 single) and eight that tracked at 7 feet or shorter. Caballero has Tampa Bay’s shortest swing, at an average of 6.9 feet. The league average is 7.3 feet.

Squared-up rate: The math behind this metric might be a lot at first glance, as it’s based on the maximum attainable exit velocity depending on the speed of the swing and the pitch, but it’s essentially a stat that shows how often hitters make contact on the sweet spot of the bat. It doesn’t have to be a hard or fast swing, either.

Naturally, Díaz leads the Rays on this front (33.5% of his swings entering Thursday, good for 20th in the Majors entering play on Friday), and Paredes (26.3% of his swings) is second. Siri (18.5%) and Arozarena (22.1%) are on the other end of the spectrum.

Blasts: Put simply, a blasted swing is squared up and fast. Squaring up a ball is obviously good, and doing so with elite bat speed is even better.

Once again, Díaz is atop the Rays’ leaderboard with blasts on 18.8% of his swings, which was sixth among qualified MLB hitters entering Thursday. Further proving that there are different ways to get the job done, Paredes (5.3% of his swings) has the Rays’ lowest blast rate.