By the middle of May, many fans are getting excited about breakout candidates while also growing restless with struggling players. Baseball is a very random sport, and sometimes we tend to forget that a lot of luck can be involved with hitters over a month and a half of plate appearances. Fortunately, there is data that can help us figure out who is overachieving and underachieving.
Thanks to Statcast, we can quantify how many home runs, triples, doubles, etc. a player should have hit compared to what they have hit by looking at the launch angle and exit velocities of balls in play. By taking that data, we can look at a metric like wOBA (which uses actual home runs, triple, doubles, etc.), and compare it to expected wOBA (xwOBA) to see what a hitters production should look like so far.
Here is a table from Baseball Savant that ranks players with 100 PA’s who have the greatest difference between their wOBA and xwOBA. In simpler terms, these are the hitters who have been “lucky” on balls in play so far this season:
Chirinos, Tapia, Peralta, McCann, and Wolters are the “luckiest” hitters so far this season. xwOBA isn’t a perfect projection metric, but it gives us a better description of what has happened. These hitters don’t exactly project forward to their current xwOBA, but we can expect their production to drop going forward.
Now the same table, but for underachievers:
To no surprise, there are some bigger names on this list. Jose Ramirez and J.D. Ramirez have been two of the better hitters in baseball over the past couple of years, but they’ve had two different types of “unlucky” seasons. Jose Ramirez, for the second year in a row, has struggled to start the season even more than one might think, as his xwOBA is just slightly above average. In comparison, J.D. Martinez is an underachiever who has had a well above average to start the year, but should have been even better, as Martinez has the 7th best xwOBA in all of baseball.
As I said with the overachievers, xwOBA isn’t a perfect projection tool with this small of a sample size, but we can expect the hitters in the second table to have an increase in production going forward.