The Cardinals selected Naile's contract from Triple-A Memphis on Monday.
St. Louis had an open spot for Naile on the 40-man roster with lefty reliever T.J. McFarland (illness) residing on the COVID-19-related injured list, but the team had to place Jack Flaherty (shoulder) on the 15-day IL to create room on the 26-man active roster. While he's up with the parent club for the first time in his career, Naile is expected to work as a multi-inning option out of the bullpen, with most of his initial usage likely to come in lower-leverage scenarios.