Friday, October 11, 2019

Postseason Pitch Skew - Dodgers Catcher Change

After the Dodgers lost the 2019 NLDS to the Nationals, a few people noticed that Los Angeles benefited from 12 more incorrectly called pitches than Washington, a stat called pitch skew. Do umpires love LA or is there a more logical and impartial explanation for why the team whose last World Series win occurred in 1988 seems to consistently lose in the postseason enjoy positive pitch skew differential over opponents?

To answer this question, we traced LA's postseason history since 2013—which was the first year of UEFL pitch skew statistics, defined as the net number of incorrectly ruled pitches that favor a given team over its opponent [e.g., the pitcher throws a pitch outside the strike zone and the home plate umpire calls it a strike...this results in a skew of +1 for the defensive team; conversely, a pitcher who throws a pitch within the strike zone called a ball earns a skew of +1 for the offensive team. Add up all skews throughout the game and you get a game skew; add all games together and you have a series skew]—and noticed something very interesting.

In 2013, the Dodgers suffered a negative 20 (-20) pitch skew against St. Louis in the NLCS (conversely, you could say that St. Louis enjoyed a +20 skew over LAD), while in 2014, the Dodgers went minus-15 against St. Louis in the NLDS. Both times, St. Louis won the series.

Framing can buy—or cost—strike calls.
In 2015, pitch skews were not statistically significant, but in 2016, something remarkable happened. In quite the turnaround, Los Angeles experienced a +15 skew (beat Washington in the 2016 NLDS), followed by +15 skew in the 2017 NLCS (beat Chicago), +10 skew in the 2018 World Series (lost to Boston), and +12 skew in the 2019 NLDS (lost to Washington).

Answer: Catcher Framing. Meet AJ Ellis, one of the worst statistical pitch framing catchers in all of baseball who just happened to be on the Dodgers from 2008 until 2016. AJ played in all six games of the 2013 NLCS and all four games of the 2014 NLDS against St. Louis. His opposing backstop for both series was Yadier Molina, one of MLB's best pitch framers at the time.

In short, Yadi "stole strikes" with his framing ability while Ellis occasionally stole balls with his bottom-10 frame attribute.

Los Angeles turned its skew luck around in 2016.
2015-16: LA Meets Analytics. The Dodgers front office then got smart and acquired a series of catchers—such as Austin Barnes and Yasmani Grandal—whose framing abilities were elite, pursuant to a metric known as Strike Zone Runs Saved or Catcher Framing (depending on where you look).

For example, in 2019, Dodgers catcher Russell Martin ranked #1 in Catcher Framing on the MLB leaderboard amongst catchers whose clubs made the postseason. Barnes ranked two spots behind Martin and rookie catcher Will Smith was two spots behind Barnes (Atlanta's Tyler Flowers was #2 and Milwaukee's Yasmani Grandal—a former Dodgers property!—was #4).

Conclusion: In other words, the Dodgers used to be very bad at the skew game thanks to substandard pitch framing. After getting bounced by St. Louis in 2014 and beaten by double-digits by then-supreme skewer Yadier Molina, LA's baseball team turned to the statistics and transacted to acquire catchers with superior—near-elite—pitch frame ability, which in turn caused LA to experience a dramatic reversal in its pitch skew fortunes.

Video as follows:

Alternate Link: How Dodgers' Catchers Steal Strikes for Positive LA Pitch Skew (CCS)


Post a Comment