Steven Matz started an early afternoon game for the Cardinals, but left after just four pitches with shoulder stiffness:

Matz had spent time on the New York Mets’  disabled list in 2016 and in 2020 with left shoulder discomfort. Rondon was called on immediately to replace Matz in the game.   

StLToday.com

This might help Matthew Liberatore, who made his debut on Saturday but was sent down. The Cardinals are doing okay. They gave a number of their regulars the day off, and still lead the Pirates 7-0 in the second inning.

Update: The runs kept coming as the Cardinals win 18-4. The Pirates did not score until the bottom of the ninth, when Yadier Molina came on to pitch.. Albert Pujols came on as a PH/DH and hit two home runs.