Editing Fastball (section)

===Sinker (two-seam fastball) ===
{{main|Two-seam fastball|Sinker (baseball)}}
The '''sinker''', synonymous with the '''two-seam fastball, two-seamer''', '''tailing fastball''', '''or running fastball''' is a type of fastball thrown with a seam orientation that induces more downward or arm-side horizontal movement compared to four-seam fastballs or cutters. Historically, distinctions have been made between these terms, but today, they are all recognized by MLB as variations of the same pitch. Differences in arm slot, spin, and velocity cause some sinkers to exhibit more vertical 'drop' or 'sink', while others 'run' or move more horizontally toward the pitcher's arm side. The unique running and sinking movement profile of the sinker makes it more likely to induce ground balls than other pitches as it sinks under the plane of the batter's swing. Not all fastballs exhibiting sinking or running movement are necessarily sinkers; four-seam fastballs thrown from a low arm slot can also exhibit sinking and running movement due to the horizontal spin axis imparted by a low or sidearm release point.<ref>{{Cite web |title=Sinker (SI) {{!}} Glossary |url=https://www.mlb.com/glossary/pitch-types/sinker |access-date=2024-07-07 |website=MLB.com |language=en}}</ref>
[[File:Sinkers three.gif|alt=sinker.gif|thumb|320x320px|Spin of 3 sinkers thrown by [[Yennier Canó]], [[Clay Holmes]], and [[Sonny Gray]] respectively, from the catcher's perspective.]]
To throw a sinker, the pitcher typically grips the ball as they would a four-seam, but with their index and middle finger parallel to the seams instead of perpendicular to them. This causes the ball to spin with two seams crossing the plane of spin instead of four.<ref>{{Cite web |last=Blewett |first=Dan |date=2022-03-28 |title=How to Throw a Sinker: The Definitive Guide in 2021 – Grips, Drills & More |url=https://danblewett.com/throw-sinker-right-way/ |access-date=2024-07-07 |language=en-US}}</ref>

Throughout much of baseball history, the reasons why a two-seam grip resulted in different ball movement compared to a four-seam fastball weren't fully understood. While it was recognized that a reduced spin rate or altered spin axis could create the distinct movement profile of the sinker, it is now understood that the distinctive movement profile of sinkers is primarily due to the [[seam-shifted wake]] (SSW) phenomenon.<ref name=":0">{{Cite web |last=Baseball |first=Driveline |date=2020-11-02 |title=An Introduction to Seam-Shifted Wakes and their Effect on Sinkers |url=https://www.drivelinebaseball.com/2020/11/more-than-what-it-seams-an-introduction-to-seam-shifted-wakes-and-their-effect-on-sinkers/ |access-date=2024-07-07 |website=Driveline Baseball |language=en-US}}</ref>

When a sinker is thrown with a moderate degree of gyro spin and properly oriented seams, the rotating seams around one pole of the baseball create a greater disturbance in the air compared to the seamless area around the other pole. This uneven drag force induces a force perpendicular to the spin direction, typically resulting in more horizontal run, vertical drop, and generally more unpredictable movement than sinkers with less substantial SSW effects. While all pitches experience SSW effects to some degree, sinkers with pronounced seam-shifted movement are understood to be particularly effective pitches, resulting in better outcomes like increased ground ball rates.<ref name=":0" />

The sinker has been a staple for many notable pitchers, often referred to as 'sinkerballers', such as: 

* [[Greg Maddux]], widely regarded as among the finest starting pitchers of all time, pitched heavily off his sinker. He relied on its substantial movement, his precise control, and its above average low 90s velocity to generate ground balls as a young pitcher. Towards the end of his career, his velocity declined into the mid 80s, but his excellent sinker helped him remain effective.<ref>{{Cite web |last=Thornley |first=Stew |title=Greg Maddux |url=https://sabr.org/bioproj/person/greg-maddux/}}</ref>
* [[Brandon Webb]], one of the most highly regarded pitchers of the 2000s before injuries forced his early retirement, was known for having one of the best sinkers in the league. He relied on this pitch to earn a [[Cy Young Award]] and two runner-up finishes from 2006 to 2008.<ref>{{Cite web |date=2023-01-21 |title=Arizona Diamondbacks: The brief and brilliant career of Brandon Webb |url=https://calltothepen.com/2023/01/21/arizona-diamondbacks-brief-brilliant-career-brandon-webb/ |access-date=2024-07-07 |website=Call To The Pen |language=en-US}}</ref>
* [[Zack Britton]], one of the most successful relievers of the 2010s, threw a mid to high 90s sinker more than 90% of the time at his peak. His sinker, now known to have benefitted from substantial seam-shifted wake (SSW) effects, consistently helped him lead the league in ground ball rates.<ref>{{Cite web |title=Zack Britton Stats: Statcast, Visuals & Advanced Metrics |url=https://baseballsavant.mlb.com/savant-player/zack-britton-502154?stats=statcast-r-pitching-mlb |access-date=2024-07-07 |website=baseballsavant.com |language=en-US}}</ref>