The Infield Defense Behind the 2019 World Series Opponents

Image courtesy of The Associated Press

As we all wait for baseball to start back up, I decided to take a look back on how the Nationals and Astros performed defensively over the course of the 2019 season, and the differences between how each team approached their defensive strategy.

According to Baseball Savant’s Outs Above Average (OAA) leaderboard, the Astros were ranked #1 in team defense with 41 OAA, and the Nationals were tied for second at 32 OAA. This means that when a team makes a single play, they are positively credited for plays that are made successfully, and negatively credited for plays they do not make. “Routine” plays increase the value by a small amount when they are made, but hurt the most (or decrease the value significantly) when they are not made. For perspective, the Orioles were ranked last at -35 OAA.

Both squads were elite in the defensive category, but boasted very different strategies. Let’s take a look at shifting- Houston shifted 2,915 times during the 2019 season with no runners on, which was the second most out of the entire league, behind the Dodgers. This image shows the density map of Houston’s shifts at Minute Maid Park:

Astros defensive shift alignment at Minute Maid Park. Image courtesy of Baseball Savant

Most often, the third baseman vacated his position (hence the lighter color at third base), and they moved an infielder partially into right field. Here’s a more simple example of what I am referencing-

Example of infield shift. Image courtesy of mlb.com

Sometimes the third baseman actually takes the position into right field and the shortstop and second baseman stay put. Houston employed both 2B and 3B in right field over the course of the season, but it was more often the second baseman. A shift is officially classified as an instance where three or more infielders are on one side of second base.

Looking at the Nationals, they shifted more than three times less than Houston did with no runners on over the course of the season:

Nationals defensive shift alignment at Nationals Park. Image courtesy of Baseball Savant

As you can see, the Nationals also placed an infielder slightly into right field when shifting. This positioning into right field was not as deep as Houston used, on average. But, the biggest difference that I notice is the positioning of two players near second base- the Nationals left their shortstop in it’s normal position more often than Houston.

I used the Baseball Savant search tool to look for left-handed batters who hit ground balls to either the shortstop, left fielder, or the center fielder against the Nationals and Astros. Here are the spray charts:

Spray charts of ground balls by lefties to SS, LF, CF. Data courtesy of Baseball Savant. Field dimensions & logos courtesy of mlb.com

In both spray charts, the blue dots are outs and the orange dots are singles. When we compare the two teams, Houston allowed significantly more singles into left field, whereas Washington created more outs at the “normal” shortstop position. This is evidence that Houston vacated the area around shortstop much more often, resulting in more left-side singles and more right-side outs by the shortstop when compared to Washington.

I wanted to investigate how these strategies really effected the outcome of opposing at-bats for both teams. I downloaded Baseball Savant data from all instances during the 2019 season where there were no runners on base in order to determine the difference between at-bats against the shift and at-bats not against the shift. Here are the results:

Results of shifting with no runners on base. Data courtesy of Baseball Savant

Both teams were positively impacted on defense when using a shift, if based purely on batting average and on-base percentage. I found it very interesting how often Houston used the shift with no runners on- Houston faced left handed batters on 47.1% of at-bats with no runners on, where Washington saw lefties 43.6% of the time. So, this means Houston also implemented shifts on right handed batters quite often. Matt Chapman was a common victim to Houston’s shift as a right-handed hitter, where he was challenged by the shift on over seventy percent of pitches faced with no runners on.

The last element of these shift strategies that I wanted to investigate is pitch selection:

Pitch selection to lefties vs. shift. Data courtesy of Baseball Savant

Many times, a shift is very reliant on a pitcher hitting his spots, because the goal is to pitch where the batter will specifically hit it to the side of the infield where the defenders are stacked. For both teams, fastballs were prominent in these at-bats, with an assortment of breaking balls and changeups mixed in. Overall fastball location did not indicate a particular dominance on one part of the plate for either team, so I decided to take a look at the breaking balls that these left-handed batters were facing:

Images intended to be visualized from catcher’s point of view. Data courtesy of Baseball Savant

The overall trend is to throw breaking balls low and inside to batters. This data accounts for both left-handed and right-handed pitchers, so the pitch location data helps to demonstrate the goal to make the left-handed batters pull the ball to the right side of the infield towards the shift.

One thing I love about watching shifts play out- do you try to hit the ball hard towards the defense, or try to put the ball in the vacated part of the infield? More likely than not, a lefty is going to get pitched inside, so each batter will attack the challenge in a different way. Hitting the ball over the fence is one way, but Daniel Vogelbach knows how to take advantage of a less-common outside pitch to beat the shift in another (my favorite) way:

All power to him, because it’s a lot harder than it looks.

OK, can we have baseball back now?