Gallen won't start as scheduled Thursday against the Cardinals after the game was postponed due to inclement weather in St. Louis, John Gambadoro of Arizona Sports 98.7 FM reports.
Gallen could be pushed back a day or perhaps skipped in the rotation. The right-hander is coming off of his worst start of the year, surrendering nine runs on 12 hits and two walks over four innings against the Twins on Saturday.