The Cards made three actual errors, plus an awful throw and a communication error, that contributed to Thursday's 9-6 loss to the Cubs. The Cards lead the league in errors (80) and by a wide margin (second-worst is Philadelphia with 69, followed by Pittsburgh with 61 and the Cubs and Padres with 60).
On Fangraphs, the Cards ranked 16th of 30 MLB teams in the site's overall defensive metric (0.1). In ultimate zone rating, they're 15th.
We know the story. While St. Louis has Kolten Wong, perhaps the best defensive second baseman in the game (and one of the better defensive outfielders in Harrison Bader as a part-time outfielder), the Cards have struggled defensively, be it with Jose Martinez wedged at first base, Matt Carpenter at times at third and Dexter Fowler in right field.