How Plate Discipline Impacts wRC+

Like many of you, I spend hours on FanGraphs trying to take in as much information as possible. One of the more fascinating statistics to me is the category of plate discipline. This includes how often a batter will swing on a pitch inside or outside of the zone, how often a batter swings and misses, and many other variables that affect a player’s approach at the plate. While these numbers alone are a good indication on how a player acts at bat, I wanted to know how these numbers affected performance. For instance, it would make sense that a higher O-Swing% could lead to less-than-average hitting. The 2015 season had Adam Jones second in O-Swing%, swinging at 47% of pitches outside of the strike zone. Pablo Sandoval led the league in O-Swing% with a 48% rate. Jones recorded a 109 wRC+ while the Kung Fu Panda had a 75 wRC+.

By breaking down these Plate Discipline statistics for the 2015 season, I believe that we can get a good answer on which statistic leads to the best performance. For my methodology, I used the wRC+ and Plate Discipline leaderboard for the 2015 season. After breaking down each statistic, I compiled a top 10 and bottom 10 wRC+. Additionally, I grouped percentages to get the number of batters and average wRC+ for certain percentages.

O-Swing %

O-Swing% = Swings at pitches outside the zone / pitches outside the zone

Top 10 wRC+ Average: 97

Name O-Swing% wRC+
Pablo Sandoval 47.80% 75
Adam Jones 46.50% 109
Avisail Garcia 45.20% 83
Marlon Byrd 43.90% 100
Salvador Perez 42.50% 87
Kevin Pillar 40.10% 93
Starling Marte 39.40% 117
Gerardo Parra 39.40% 108
Freddy Galvis 39.20% 76
Nolan Arenado 38.50% 119

 

Bottom 10 wRC+ Average: 132

Name O-Swing% wRC+
Brett Gardner 22.90% 105
Ben Zobrist 22.60% 123
Matt Carpenter 22.50% 139
Paul Goldschmidt 22.40% 164
Jose Bautista 22.20% 148
Carlos Santana 21.10% 110
Francisco Cervelli 20.90% 119
Dexter Fowler 20.90% 110
Curtis Granderson 19.90% 132
Joey Votto 19.10% 172

 

Percentage Count Average wRC+
40%-48% 6 91
30%-39% 73 106
20%-29% 60 117
< 20% 2 152

O-Swing% gives us a pretty good indication of a player’s overall performance. It’s no surprise that patience and a good eye are part of a skill set that leads to a higher wRC+. For each 10-percent decrease of O-Swing percentage, batters see an increase of over 10 points for their wRC+. The top 10 wRC+ compared to the bottom 10 also tells a compelling story of what O-Swing tells us. In the top 10, we see a couple of above-average hitters like Starling Marte and Nolan Arenado. However, we also see five of the top 10 with a wRC+ under 100 and one hitter (Marlon Byrd) at 100. On the other side of the spectrum, there isn’t a hitter under 100 wRC+ in the bottom 10. The difference in wRC+ between the top and bottom 10 is 35, the biggest difference between all the statistics.

Let’s look at two very different extremes: Joey Votto and Pablo Sandoval. Sandoval had an O-Swing% of 48 percent while Votto had a 19 percent rate, which means that while Sandoval is swinging at almost half of the balls he faces, Votto is taking a little more than 80% of pitches out of the zone. Sandoval faced 1848 pitches (1287 strikes to 561 balls) while Votto faced 3020 pitches (1644 strikes to 1376 balls). Sandoval’s more than double strike-to-ball ratio and Votto leading the league in walks can both be explained by their O-Swing percentage.

Z-Swing %

Z-Swing%  = Swings at pitches inside the zone / pitches inside the zone

Top 10 wRC+ Average: 111

Name Z-Swing% wRC+
Marlon Byrd 83.20% 100
Brandon Belt 80.90% 135
Adam Jones 80.60% 109
Avisail Garcia 78.90% 83
Billy Burns 78.80% 102
Carlos Gonzalez 78.10% 114
Ryan Howard 77.80% 92
Starling Marte 77.50% 117
Kris Bryant 76.20% 136
Brandon Crawford 76.10% 117

Bottom 10 wRC+ Average: 115

Name Z-Swing% wRC+
Carlos Santana 57.90% 110
Logan Forsythe 57.70% 126
Joe Mauer 57.50% 94
Brock Holt 57.40% 98
Brett Gardner 55.80% 105
Brian McCann 55.80% 105
Mookie Betts 55.70% 119
Mike Trout 55.60% 172
Ben Zobrist 55.40% 123
Martin Prado 53.20% 100

 

Percentage Count Average wRC+
80%-83% 3 115
70%-79% 51 111
60%-69% 75 110
50%-59% 12 114

The first thing that I noticed when looking at the Z-Swing charts is the duplication of names from the O-Swing charts. Adam Jones, Avisail Garcia, Marlon Byrd, and Starling Marte showed up on both the O and Z Swing percentage top-10 while Ben Zobrist, Carlos Santana, and Brett Gardner appeared on both bottom-10 lists. This is a very mixed bag of players for both the top and bottom. Both have a 100 wRC+ hitter, the epitome of average. Both have seven hitters batting above 100 wRC+ meaning that both lists also have two hitters batting below 100. The top and bottom 10 averages are almost even. The one outlier that separates them is Mike Trout in the bottom 10 with a 172 wRC+. Seeing the same name on multiple lists can tell us a lot about a player. Someone like Marlon Byrd will swing at most of the pitches you send his way while Ben Zobrist will take a pitch outside of the zone about 77% of the time but will also take a strike 45% of the time as well.

O-Contact %

O-Contact% = Number of pitches on which contact was made on pitches outside the zone / Swings on pitches outside the zone

Top 10 wRC+ Average: 104

Name O-Contact% wRC+
Nick Markakis 86.10% 107
Michael Brantley 84.60% 135
Daniel Murphy 83.50% 110
Ender Inciarte 82.30% 100
Melky Cabrera 82.10% 91
Wilmer Flores 82.00% 95
Jose Altuve 81.70% 120
Ben Zobrist 80.90% 123
Angel Pagan 80.80% 81
Yadier Molina 80.20% 80

 

Bottom 10 wRC+ Average: 104

Name O-Contact% wRC+
Anthony Gose 55.00% 90
Avisail Garcia 55.00% 83
Nick Castellanos 53.20% 94
Ryan Howard 52.80% 92
Michael Taylor 52.10% 69
Justin Upton 51.50% 120
Addison Russell 51.10% 90
Chris Davis 50.90% 147
Kris Bryant 49.20% 136
Joc Pederson 49.00% 115

 

Percentage Count Average wRC+
80%-86% 10 104
70%-79% 46 103
60%-69% 60 118
50%-59% 23 105
< 50% 2 126

Similar to Z-Swing%, O-Contact doesn’t show much disparity between the top and bottom 10. In fact, they’re identical at 104 wRC+. A higher O-Contact gives a batter more balls in play, but doesn’t always lead to success. My initial thought was that swinging at a pitch way out of the zone can lead to weak contact, and usually an out. The fact the top and bottom are identical shows that this isn’t always the case.  It also makes sense why the middle of the pack (60%-69%) has the greatest wRC+ (besides the small sample size of < 50%). These batters are still able to make contact with pitches outside of the zone more than half of the time, but also miss the pitch enough of the time where they don’t make bad contact.

Z-Contact %

Z-Contact%  = Number of pitches on which contact was made on pitches inside the zone / Swings on pitches inside the zone

Top 10 wRC+ Average: 110

Name Z-Contact% wRC+
Daniel Murphy 97.50% 110
Ben Revere 96.70% 98
Michael Brantley 96.30% 135
Yangervis Solarte 95.50% 109
Martin Prado 95.40% 100
A.J. Pollock 94.60% 132
Jose Altuve 94.60% 120
Ian Kinsler 94.50% 111
Erick Aybar 94.30% 80
Ender Inciarte 94.20% 100

 

Bottom 10 wRC+ Average: 125

Name Z-Contact% wRC+
Mark Trumbo 80.90% 108
Brandon Belt 80.70% 135
J.D. Martinez 80.60% 137
Nelson Cruz 79.30% 158
Justin Upton 78.00% 120
Michael Taylor 77.40% 69
Joc Pederson 77.00% 115
Chris Davis 76.50% 147
Alex Rodriguez 76.50% 129
Kris Bryant 75.80% 136

 

Percentage Count Average wRC+
90%-98% 55 106
80%-89% 79 113
70%-79% 7 125

Z-Contact was the most surprising statistic in terms on its effect on wRC+, until you look at the names in the bottom 10. One would expect that hitters that hit more pitches in the zone would be the better performers. However, the bottom 10 is filled with power hitters, leading to the main difference in wRC+. Davis and Cruz were number one and two in terms of home-run leaders in 2015. In fact, besides Michael Taylor, the bottom 10 is all in the top 50 for home runs in the MLB. The list makes sense as players like Chris Davis are trying to “Crush” the ball out of the park and swing harder than someone in the top 10 like Martin Prado.

SwStrike %

SwStr% = Swings and misses / Total pitches

Top 10 wRC+ Average: 110

Name SwStr% wRC+
Avisail Garcia 17.30% 83
Marlon Byrd 17.20% 100
Ryan Howard 16.60% 92
Kris Bryant 16.50% 136
Michael Taylor 16.00% 69
Chris Davis 15.60% 147
Carlos Gonzalez 15.20% 114
J.D. Martinez 14.90% 137
Mark Trumbo 14.60% 108
Joc Pederson 14.00% 115

 

Bottom 10 wRC+ Average: 105

Name SwStr% wRC+
Ian Kinsler 5.20% 111
Ender Inciarte 4.90% 100
Andrelton Simmons 4.90% 82
Angel Pagan 4.40% 81
Martin Prado 4.30% 100
Ben Zobrist 4.20% 123
Nick Markakis 4.10% 107
Ben Revere 4.10% 98
Daniel Murphy 3.90% 110
Michael Brantley 3.10% 135

 

Percentage Count Average wRC+
15%-18% 7 106
12%-14.9% 20 107
9%-11.9% 36 117
6%-8.9% 50 114
3%-5.9% 17 106

Not surprisingly, the top 10 for SwStrike looks a combination of both the O-Contact and Z-Contact bottom 10. Obviously if your contact is low, you’re going to have more swings and misses. The main factor that stood out to me looking at the top and bottom 10 is the deviation of wRC+. The top 10 is all over the place, having players like Kris Bryant with a 136 wRC+, Michael Taylor with 69, and every level of player in between. The bottom 10 has less variation, providing a more consistent group of hitters.

Totals

Category Top 10 Bottom 10 Difference (Bottom to Top)
O-Swing% 97 132 35
Z-Swing% 111 115 4
O-Contact% 104 104 0
Z-Contact% 110 125 15
SwStr% 110 105 -5

 

As evidenced by the chart, the main statistic in regards to plate discipline to show a great change in performance that compares the bottom to the top level is O-Swing percentage. Z-Contact seems to also be relevant when evaluating and predicting a player’s performance.





newest oldest most voted
John Avsec
Member

Very good article, interesting to see that the most disciplined players are generally the most productive. You see a lot of guys who are free swingers generally with a lot of XBH and as a result you assume that they end up being the most productive of the lot. Carlos Santana, is an especially interesting case. Very disciplined yet only a 110 wRC+, you’d thin that’d be a lot higher with his discipline.

Eli Ben-Porat
Member
Member

How much of the WRC+ gain is related to an increase in OBP? In other words, does it make them more effective BIP hitters, or are we simply saying that not swinging at balls leads to more walks.