Which Padres Have Changed Their Approach?

We’re at an interesting point in the season for looking at stats. During the first month of the year, everybody pretty much knows that most stats aren’t worth a lot when measuring future expectations. Now that we’re about four months into the season, that feeling seems to have has gone away.petco park

The amount of time it takes for a stat to become stable is a complicated subject. But here are two things I believe:

  1. Even “advanced” stats like wOBA or wRC+ are not all that useful to help predict the future even at this point in the season.
  2. Stats that players have more direct control over are the most useful right now.

I was curious to find out if any Padres have changed the approach at the plate this season. And there aren’t many more stats that hitters have control over than what pitches he chooses to swing at. So, lets dive in!

I pulled up the Fangraphs O-Swing%, Z-Swing%, and Swing% data for a group of players who have seen a good chunk of playing time for the Padres in both 2016 and 2017. Then I just subtracted 2017 totals from 2016, and looked for differences.

I made a couple exceptions: Austin Hedges‘ info is from 2015 since there is more of it. I also included Matt Szczur‘s data with the Cubs and Hector Sanchez‘s with the White Sox in 2016.

Swings at pitches outside the zone

2017 O-Swing% 2016 O-Swing% Difference
Cory Spangenberg 34% 24% 10%
Matt Szczur 23% 32% -8%

Swings at pitches inside the zone

2017 Z-Swing% 2016 Z-Swing% Difference
Hunter Renfroe 68% 84% -16%
Hector Sanchez 68% 78% -10%
Cory Spangenberg 64% 72% -8%
Matt Szczur 67% 75% -8%
Ryan Schimpf 60% 68% -7%

Overall swings

2017 Swing% 2016 Swing% Difference
Matt Szczur 43% 53% -9%
Hunter Renfroe 48% 57% -9%
Ryan Schimpf 38% 43% -5%

Cory Spangenberg looks the worst in all this. He’s swinging at roughly the same number of pitches, so no large differences to earn him a spot in the Swing% chart above. But he’s swinging at 10% more balls and 8% fewer strikes. His approach is an outlier and seems concerning.

Both Matt Szczur and Hunter Renfroe are swinging a lot less. The former’s change is across the board, while Renfroe is mostly swinging at fewer strikes. I wonder if Renfroe is consciously working on something as he’s continually swung at fewer pitches throughout his young career. He appears to have made an adjustment in mid-May by kicking his not-swinging into high gear, at which point he also increased his walk totals. Here are those numbers plotted on the same graph, courtesy of Fangraphs:

Hunter Renfroe Walk and Swing Percentage

Here’s a color coded graph of the rest of the team’s plate discipline changes:

padres swing percentage

The number of players swinging at fewer pitches in the zone is a little unnerving, with Austin Hedges bucking that trend the most and hammering at more strikes.

Here’s the team as a whole, which we can use to find out if there might be a team-wide philosophy change, perhaps pushed by coaches. It’s worth mentioning at the risk of stating the obvious that these are two different groups of players:

2017 and 2016 Padres

O-Swing% Z-Swing% Swing%
 2016 Padres 30.8% 66.1% 46.7%
2017 Padres 31.6% 65.1% 46.6%
Estimated MLB Average 30% 65% 46%

We see the same trend we noted in the individual tables above: fewer swings at strikes and more swings at balls. It’s not a great sign, hopefully the team has noticed and it’s something they’re looking to address.

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