Part of the problem has been a change in personnel. 4 of the 9 positions have seen changes in the past three years. Additionally, mistakes defensively could be attributed to positioning in the field. Investigating the locations of players on the Cardinals could give us an answer to where they are falling short.
Baseball Savant provides a detailed image of player positioning each year. Looking at the graphs and images, one thing stands out to me: player depth. In 2023, infielders are playing much further than before. The shift does require all four infielders to be on the dirt; however, when comparing the Cardinals' positioning to teams such as the San Diego Padres (28 OAA) and Milwaukee Brewers (25 OAA) there are some major differences.
When looking at key differences between the Cardinals and the Padres, the Cardinals appear to have a bigger hole on the left side of the infield between shortstop and third base. While the Padres' third basemen typically shade back and up the line or in near the grass towards second base, the Cardinals plant their third basemen straight up, primarily off the line and about midway on the dirt. Their straight-up third basemen OAA is a net zero, while their toward SS/3B hole is a positive 4. Perhaps the team could benefit by sliding Arenado slightly to his left more often. As discussed above, Arenado could also benefit by moving closer to the line in certain situations. This would help his lateral movement towards third base. Rather than playing straight up, Arenado could move in either direction at the start of the at-bat based on batter tendencies.
Another stark difference in positioning between the Cardinals and Padres would be second base. The Padres play their second basemen closer to first base or straight up whereas the Cardinals place their second basemen directly behind the bag for a majority of at-bats. The Cardinals have a -2 OAA up the middle, but they have a positive 2 OAA when shaded toward the 1B/2B hole. Sliding Nolan Gorman over to his left (closer to first) more often may benefit the defense, especially since Tommy Edman is back at shortstop most often now and can cover a fair amount of ground.
Both the Padres and Brewers place their center fielders either directly left or directly right of center. The Cardinals, however, appear to work on a continuum of positions for their center fielders across a straight line. In 2022, the Cardinals' center fielders did not play in the gaps in the outfield. Rather, they shaded slightly left or slightly right, depending on the batter. This year, however, they are playing in the gaps much more often. When shading either direction, the center fielders have a positive 6 OAA. Contrarily, they are only a positive 1 when playing in the gaps. In 2022, center fielders netted +12 OAA when only shading either direction.
With slight adjustments in positioning, paired with patience (see Gorman and Walker), the Cardinals should see improvements in their defensive metrics. While it is unlikely they vault into the top-15 for Outs Above Average this year, the Cardinals could see great improvements next year defensively. Hopefully, this will help the team perform better in 2024.