PBR Introduces Sink Score
February 17, 2022
Sink Quantified
Until now, the word 'sink' has been used to describe a fastball that visually drops and runs arms side through the strike zone. You can say fastballs with extreme sink have lower spin with horizontal movement characteristics, or low backspin. Submarine pitchers can impart topspin which increases their ability to create sink on their fastball.
Sinking fastballs visually drop through the strike zone generating higher ground ball percentages when thrown down in the strike zone. PBR’s goal was to be able to objectively quantify fastballs with sink characteristics across levels.
What is a Sink?
Sink is defined as a fastball that visually drops and runs arms side through the strike zone.
Sink Score
Using advanced pitch data metrics, PBR’s analytics department has developed a sink score to easily compare fastballs across multiple levels.
Sink+ Stats
The Sink+ stat takes and normalizes our Sink score across an entire level. Sink+ is calculated by dividing a Pitcher’s sink by the mean sink of the level of play and multiplying by 100. In other words, the mean Hop is set to 100 and 1 unit above or below that is equal to being 1% above or below that mean for the level of play.
MLB SINK+ LEADERS 2021
| RANK | PITCHER | YEAR | SINK+ |
| 1 | Tanner Houck | 2021 | 151 |
| 2 | Logan Webb | 2021 |
150 |
| 3 | Randy Dobnak | 2021 |
148 |
| 4 | Aaron Bummer | 2021 |
148 |
| 5 | T.J. McFarland | 2021 | 146 |
| 6 | Ryan Weber | 2021 | 143 |
| 7 | Justin Lawrence | 2021 | 141 |
| 8 | Anthony Bender | 2021 | 141 |
| 9 | John King | 2021 | 139 |
| 10 | J.C. Mejía | 2021 | 137 |
| 11 | Nick Sandlin | 2021 | 135 |
| 12 | Carlos Martínez | 2021 | 134 |
| 13 | Jeurys Familia | 2021 | 133 |
| 14 | Aaron Loup | 2021 | 132 |
| 15 | Luis Castillo | 2021 | 131 |
| 16 | Humberto Castellanos | 2021 | 131 |
| 17 | Josh Fleming | 2021 | 128 |
| 18 | Richard Bleier | 2021 | 128 |
| 19 | Marcus Stroman | 2021 | 128 |
| 20 | Chris Mazza | 2021 | 127 |
MLB SINK+ LEADERS 2015-2021
| RANK | PITCHER | YEAR | SINK+ |
| 1 | Austin Brice | 2019 | 155 |
| 2 | Jared Hughes | 2018 |
154 |
| 3 | Carson Smith | 2015 |
153 |
| 4 | Randy Dobnak | 2020 |
152 |
| 5 | Tanner Houck | 2021 | 151 |
| 6 | Jared Hughes | 2019 | 150 |
| 7 | Logan Webb | 2021 | 150 |
| 8 | Jared Hughes | 2020 | 149 |
| 9 | Randy Dobnak | 2021 | 148 |
| 10 | Aaron Bummer | 2021 | 148 |
| 11 | Trevor Hildenberger | 2018 | 148 |
| 12 | Justin Masterson | 2015 | 148 |
| 13 | Phillips Valdez | 2019 | 147 |
| 14 | Aaron Bummer | 2020 | 146 |
| 15 | Andrew Triggs | 2016 | 146 |
| 16 | T.J. McFarland | 2021 | 146 |
| 17 | Zach Duke | 2016 | 146 |
| 18 | Nate Adcock | 2015 | 145 |
| 19 | Cory Gearrin | 2016 | 144 |
| 20 | T.J. McFarland | 2019 | 144 |
SUMMARY
We now have a simple way to objectively compare fastballs with sink characteristics between levels and over time with the Sink+ stat. The effectiveness of a fastball is very dependent on outside factors including location and pitch repertoire. In general, fastballs with higher Sink+ are more difficult to hit.