Double Plays

Introduction.

As you know, a double play happens when the Diamondbacks’ fielders put out two opponents’ players in one play. Two facts made me wonder about double plays:

• In games through 3 May, The Fielding Bible ranked the Diamondbacks defense as third best in the Majors. Did double plays make a difference?
• Were more double plays possible because the Diamondbacks kept runners at first base by leading the Majors in least stolen bases allowed?

Before we answer those questions, let’s look at the Diamondbacks.

How long were the Diamondbacks’ streaks of double plays?

This season, the longest streak of consecutive games with the Diamondbacks defense executing double plays was five. It happened April 8 to April 12, against the Dodgers and Brewers. The Diamondbacks executed eight double plays during those five games.

A recent streak of double play games ended at 4 games (28 April to 2 May).

This season, the longest streak of games without the Diamondbacks executing a double play was 4 games. It happened twice, from 30 March to 2 April against the Dodgers, and 18-21 April against the Cardinals and the Padres

Which Diamondbacks contributed to double plays?

The unsung contributors were the pitchers because their pitches resulted in fieldable balls-in-play. Looking at this season 13 Diamondbacks participated in the first 24 double plays. That really surprised me! That was about double my expectation.

There were two types of participation in double plays:

• Who fielded the ball-in-play?
• Who continued the play?

The following table shows how the Diamondbacks contributed.

Data from MLB.com.

Three players had the highest totals:

• Christian Walker participated in the most double plays. Especially noteworthy were the 4 plays that he fielded the ball in play. His outstanding defense complimented his outstanding offense. His 7 home runs and 25 RBIs lead the Diamondbacks.
• Geraldo Perdomo participated in the second most double plays. His outstanding defense complimented his outstanding offense. His season 1.109 OPS was the highest on the Diamondbacks.
• Ketel Marte participated in the third most double plays. Again, his outstanding defense complimented his excellent offense.

Except that the Diamondbacks were ahead by 7 runs, one double play would have been spectacular, Alek Thomas caught the ball in center field and threw out the runner at home plate. Nevertheless, his play gets honorable mention.

Did double plays make a difference?

As far as winning the game, it appears other factors were more important:

• When Diamondbacks’ defenders executed one double play in a game, their record was 4 wins and 6 losses.
• When the Diamondbacks’ defenders executed two double plays in a game, their record was 4 wins and 3 losses.

As far as Win Probability Added (WPA), double plays made a difference. Six double plays had a WPA exceeding 10%. The Diamondbacks’ average WPA per double play was 6%. WPA data from Baseball Reference.

The most impactful double play happened on 12 April. Andrew Chafin was pitching to Willy Adames. The Brewers were down 2 runs, but had runners on first and second with no outs. The double play added an 18% chance of winning! the game ended well, the Diamondbacks kept the two run lead and won the game.

By allowing the least stolen bases, did the Diamondbacks have above-average opportunities for double plays?

Looking at total double plays executed this season, the Diamondbacks rank in a tie for 16th-20th place. The Diamondbacks double plays per game was below the average in the Majors (.774 vs .810). Although the number of double plays was about average, perhaps looking at opportunites will provide insights.

Definition of opportunity for this question. An opportunity is defined as a ball-in-play with a runner on first and less than 2 outs in an inning. This data can be obtained from the Baseball Savant website. Please note that this definition is most insightful despite the caveat that there are opportunites without a runner on first base, which rarely result in double plays. This season though 3 May, 95.8% of Diamondbacks’ executed double plays happened with a runner at first base.

This season through 3 May, the Diamondbacks had less opportunites per game than the average in the Majors (4.7 vs 5.0). And the Diamondbacks opportunities per game was the lowest since 2019.

The surprising answer is preventing stolen bases did not increase the Diamondbacks’ opportunites for double plays or their actual double plays.

Let’s look at a better question.

Did the Diamondbacks have an above-average double plays per opportunity?

This is a better question because it addresses how well the Diamondbacks played when they had opportunities. The answer revealed something significant.

The Diamondbacks’ double plays per opportunity were above the average in the Majors (.164 vs .163). Although harder to find, this answer shows how well the Diamondbacks play defense.

Summary.

Top level statistics appear to show that executing double plays did not make a difference for the Diamondbacks. Deeper level statistics (win probability added and double plays per opportunity) show that executing double plays did make a difference and reflect excellent defense by the Diamondbacks.