A win over the Reds drops the magic number for the Cardinals down to 8. The Pirates won in Colorado which keeps the division lead still at four games.
Cardinals magic number to clinch the Central Division — 8
The Royals dropped the series opener with Seattle and the Twins won over Cleveland so the Royals magic number is unchanged.
Royals magic number to clinch the Central Division — 3
The magic number is determined by taking 163 and subtracting the number of wins for the Cardinals (or Royals) and subtracting the number of losses for the Pirates (and Twins) respectively.