The Cardinals assigned Kaminsky to their alternate training site in Springfield on Thursday.
Kaminsky was one of four players sent packing from big-league camp as the Cardinals trimmed down their group ahead of Opening Day. A 2013 first-round pick of the Cardinals, Kaminsky is in his second stint with the organization after he was previously traded to the Indians in 2015 before joining St. Louis on a minor-league deal this winter. He split time between Triple-A Columbus and Double-A Akron last season, compiling a 3.54 ERA and 1.25 WHIP across 56 innings.