The Miami Marlins hitters in new StatCast technology

We had a lot of questions about the Miami Marlins and their hitters heading into the 2016 season, and information on how they would perform has been reviewed several times over. However, with the advent of StatCast from MLB Gameday, we have even more information about what makes hitters tick and what kinds of contact make for the most value. Last week, Rob Arthur of FiveThirtyEight pointed out a chart that combined two critical aspects of what makes a good swing: exit velocity and launch angle.

The relationship between a batted ball’s launch angle, exit velocity and linear weights scoring value (a measure of the runs a play adds relative to average) is complicated.² The very best hitters in MLB tend to smack lots of balls with launch angles around 25 degrees and exit velocities above 90 miles per hour, corresponding to the area of the plot rich in such valuable plays as home runs and doubles. Worse hitters, by contrast, have a tendency to make contact at sharper angles, where positive run values are harder to come by.

That sweet spot for swings appears to be to create a launch angle of just around 25 degrees. By looking at that plot, you can see that the angles around 25 degrees produce positive results when hit at weaker exit velocities and progress, dipping in value at around 80 mph and regaining value as likely extra-base hits and home runs as the velocity approaches 100 mph.

Which Marlins put the most balls in play with launch angles of the line-drive variety? Derek Dietrich and Dee Gordon led the way on balls in play in launch angles between 22 and 28 degrees. Dietrich put up about 25 such elite line drive balls, which constituted 2.3 percent of all of his pitches overall. Gordon, on the other hand, got 38 of these balls, which was good for 1.7 percent of his pitches seen.

One would figure this would be good for both players, but the results are actually fairly interesting. Here are the two charts for each player's batted balls with those launch angles.

It should be noted that batted balls at this launch angle almost always end up in the outfield, as these are essentially line-drive type hits. The difference between these two is the success that they had on these hits. Dietrich got good value out of putting balls at this angle, batting .560 on the 25 batted balls and slugging 1.200! For Dietrich, hitting balls at this angle is effective.

For Gordon, it was less so. He mustered just nine hits in those 38 balls in play, batting .237 and slugging .421. Why was it more difficult for Gordon to get value out of balls like these than it was for Dietrich? The difference likely lies in the exit velocity on these balls.

The problem in this range is that there is a brief drop in value among balls hit at this angle once you reach a certain exit velocity. From the FiveThirtyEight article:

Batted ball value peaks at 70 mph before dipping down to its lowest around 85 mph in a brief valley before the value picks up again. It breaks back even with the average batted ball at just about 95 mph exit velocity and grows very quickly by that point. The essential problem is that if you hit a soft line drive of 60 to 75 mph, you get value from having it fall in front of outfielders for soft base hits. Once the velocity gets higher, the trajectory tends to take the batted ball towards the normal locations for outfielders, making for easier outs. Once you get to 95 mph or above, these are more hard-hit line drives that get past outfielders or above their heads, and anything beyond that starts hitting or going over walls.

Dietrich has an advantage in this regard in that he has power. Hitting several batted balls, especially in the pull field where power is most utilized, provides him great value. You can see that most batted balls he sends out are at 90 mph or greater, meaning that the value of those balls is beginning to increase in value. Gordon, on the other hand, hits a lot more batted balls at around an 80 mph range, right around the valley of value for line drives.

Where Gordon may have more value is on ground balls, where his speed is of significant importance in terms of extracting use. According to the FiveThirtyEight article, the fastest runners like Gordon extract the most value from ground balls at every level of exit velocity, especially at lower launch angles. Looking at grounders with an exit velocity lower than 80 mph, these represent both the lightest grounders that have a possibility of being beat out before being fielded and those standard ground balls that are commonly hit to infielders at their normal playing depths. On those types of balls in play, Gordon picked up 37 hits in 157 non-sacrifice bunt chances, an average of .236. Compare that to Christian Yelich, a player who hits a lot of ground balls, but not nearly as many weak grounders. He only picked up seven hits, five singles and two doubles, in similarly weakly-hit grounders. That is a .101 batting average with a .169 slugging percentage.

Both Gordon and Yelich hit about the same number of hard-hit grounders last season, but even in those last season, Gordon held the edge. Gordon hit .459 (including fielding errors as singles) and slugged .494 on his 174 grounders hit harder than 80 mph, while Yelich hit .409 and slugged .438 on those balls. Of course, this is all one season's worth of work, but it points to the general principle that we suspected: Gordon needs to focus on solid grounder-based contact to be successful, whereas Yelich, Dietrich, and others can hit the ball in the air for better success.

The data we can access now from StatCast is a sliver in what should be the next big thing in revolutionary baseball research. The Marlins have a sample of interesting players about whom we learned a little more thanks to this kind of data.