The Cardinals are slated to call up Gastelum from Triple-A Memphis, Jeff Jones of the Belleville News-Democrat reports.
He's expected to be promoted either in between games during Tuesday's doubleheader or before Wednesday's contest. Gastelum has been on a roll at Memphis, turning in 18 consecutive scoreless appearances. Overall, the changeup artist has collected a 2.27 ERA and 49:17 K:BB over 43.2 innings this season. The Cardinals will need to free up a spot on the 40-man roster for Gastelum.