Heavy rain moved into the area just before the top of the eighth, which opened with shortstop Eugenio Suarez dropping a routine infield popup. The umpires then summoned the groundscrew to cover the field. After a 67-minute delay, the game was officially suspended.
The Cardinals will resume play on Saturday holding a four-game National League Central lead over the Pirates and at least a 6 1/2-game advantage over the Cubs, who were leading the second game of a doubleheader when the Cardinals' game was suspended.
St. Louis will have a fresh bullpen ready for Saturday, as starter John Lackey pitched all the way up until Friday's stoppage.