Analytics 101: Sweet Spots, Barrels, and… Alex Avila?

The advent of Statcast has given us many new insights into all phases of the game. For hitters these insights come from the ability to measure batted balls more granularly than just if they turned into a hit or an out. More specifically, it has given us the ability to measure a batted ball’s exit velocity (the speed at which the ball leaves the bat) and launch angle (the vertical angle at which the ball leaves the bat).

An informative way to slice and dice launch angle data is a metric called Sweet Spot % which is a classification assigned when a batted ball is hit with a launch angle between 8 and 32 degrees. Balls hit in this angle range tend to be line drives, which usually generate high batting averages and slugging percentages, relative to groundballs or high fly balls. As a rule of thumb, not hitting the ball on the ground is a good thing. This is mostly because ground balls turn into outs more frequently than balls hit in the air and even if they do get through for hits they are most often singles.

Below is the 2019 MLB top 10 in Sweet Spot %, among qualified hitters:

We see a couple of familiar names among baseball’s leaders. This makes sense if we think about Arraez and Polanco’s typical batted ball – they hit a lot of line drives, especially last year.

To investigate further, we can bring in exit velocity combined with launch angle. Together, these two data points can help us measure hitter performance in areas that they can exert some degree of control – how hard they hit a pitch and whether they hit the ball on the ground or in the air.

Since 2015, Statcast has used these measurements to track a metric called “Barrels” which is a classification assigned to batted balls with an exit velocity and launch angle combinations that lead to at least a .500 batting average and 1.500 slugging percentage. In general, hitting the ball with a high exit velocity (usually above 98 mph) and at an angle that makes it difficult to turn that batted ball into an out (usually best between 10 and 30 degrees, roughly) is preferred and leads to better outcomes. This is especially true for power hitters that teams count on to drive the ball and create runs. Barrels are perhaps best visually explained with the below graphic from MLB:

So how do the Twins perform when it comes to barrels? For that question, we can check out the Statcast leader board at baseballsavant.mlb.com. Filtering on 2019 qualified hitters and barrels as a percentage of plate appearances, we quickly see some familiar names:

That’s four 2020 Twins in the top 15 across the MLB in a list that is includes some of the best run producers and power hitters in the game today. Close observers will also see another familiar name in the list – former Twins/current Tigers first basemen C.J. Cron. Not shown in the table, but also relevant is that these same four Twins – Cruz, Sano, Garver, and Donaldson – were among the MLB top ten in hard hit %, defined as the percentage of balls hit above 95 mph or above. Each is above 50%. Additionally, Sano (94.4 mph) Cruz (93.7 mph), and Donaldson (92.9 mph) were among the top 10 in average exit velocity.

The statistics I’ve shown thus far have been limited to qualified hitters (meaning those that averaged 2.1 or more plate appearances per team game) and are littered with Twins. It makes sense that we’d see Twins among the leaders in these stats – the team did set the MLB record for home runs in a season after all. However, if we play around with the filters to look beyond qualified hitters we find something else interesting – Alex Avila. If I set the minimum at 50 batted ball events the Twins’ new backup catcher starts to show up near the top of the lists in sweet spot %, hard hit %, and barrels.

There is naturally more uncertainty that comes with playing with small sample sizes like this, but it is interesting. I’ve also added former Twins catcher Jason Castro to the table – and he was also up in the top of the lists in 2019. If we compare the two players we see quite a few similarities. Both are left-handed hitters, which complements the righty swinging Mitch Garver from a platoon standpoint. Both had underlying batted ball statistics that were quite strong and this data also shows both Castro and Avila are balanced, ranking highly in both sweet spot % and barrels.

This data perhaps gives us some insight into why the Twins front office was interested in bringing Avila aboard to replace Castro. With these numbers we might expect Avila to provide a reasonable approximation of Castro’s 2019 production but for about $2.5M less in annual cost.

Have questions or ideas for future breakdowns? Please leave them in the comments.