FG on Fox: The Top Plate-Discipline Improvements of 2015

We usually turn to the tried and true method of analyzing players season by season. There’s a point at which we have to demarcate sections of a player’s career, and the beginning and end of a season give us a handy and obvious way of doing so. But there are often many changes and adjustments that go on within a season, and looking at six months of baseball as one unit misses a lot of trends that we might otherwise notice. With that in mind, today we’re going to look at a few players who improved their eye and contact rate at the plate from the first half of the 2015 season to the second, giving consideration to how those improvements might help them in the upcoming 2016 season.

We’ll be looking at the most-improved players for two main plate discipline statistics: the rate of swings at pitches outside of the strike zone, and the rate of contact on pitches swung at in the strike zone. There are more plate discipline categories than just these two, but these carry a lot of weight in respect to strikeout and walk rates, so this is a great place to start. The other good news is that these types of improvements have been shown to stabilize over a short period of time – that is, once they show up, it doesn’t take too long before we can be confident that what we’re seeing is actually an improvement instead of just random noise.

To begin with, let’s look at which players showed the most improvement at laying off pitches outside of the strike zone (called O-Swing %) during the second half of the season compared to the first. I’ve included each player’s first and second half stats, the difference between them, and the second half O-Swing % minus a three year average for each player. That final column is to try to discern whether the second half improvement was actually real, or whether it was simply a response (regression) to a first half that was outside of the player’s “normal” performance from the past three years. For players with less than three years of MLB service time, as much playing time as possible was included in the final column. Let’s see our top 10 for O-Swing improvement:

Evan Gattis basically became a completely different hitter in the second half of the season. Jeff Sullivan already pointed this out in September, and this should act as further confirmation: after a rough first half in which he struck out 22.4% of the time, Gattis showed a remarkable transformation, cutting down on the rate of swings at out-of-zone pitches by 13.5%. That lowered his second half strikeout rate to 16.3% — better than league average – and raised his walk rate from 3.5% to a more palatable 6.8%. These are very good signs for him getting back on track for the Astros in 2016 after a tough campaign last season.

Read the rest on Fox Sports.