 After spending the rest of 1954, and all of 1955 through 1957, in minor league baseball, he was selected in the winter 1957 Rule 5 draft by the Cardinals and began 1958 on their roster.In his only National League appearance, against the Chicago Cubs at Busch Stadium April 15, Flanigan hurled one inning in relief and allowed two hits and one run, the latter coming on a home run by Cub catcher Cal Neeman.He then was returned to the White Sox' Indianapolis Indians affiliate, from which he had been drafted.