Daniel Ponce de Leon is expected to take Mikolas' place in the rotation for the time being, according to Saxon.
The Cardinals also called up pitcher Jacob Woodford. And there is the possibility that Kwang Hyun Kim could get a crack at the rotation after starting the season in the bullpen.
Ben Frederickson @Ben_Fred
Could be. Hard to say. Spin zone is in motion. Questions about Mikolas velocity dip were brushed off, and now this, with team confirming Ponce was being prepped for start in case Mikolas injury confirmed. A six-man rotation could have helped keep all 6 on starter's sched. https://t.co/lhhIAeXO2w
Mikolas had dealt with arm issues in spring training but Derrick Goold of the St. Louis Post-Dispatch reported that the pitcher had been "reassured that rest and non-surgical treatment would promote healing. The game's stoppage due to the coronavirus pandemic bought him addition time to recover and then go through a throwing program that had him ready for 'Summer Camp.'"
But Mikolas had velocity issues during his exhibition appearance and ultimately his arm issues will require surgery to correct.
The 31-year-old started 32 games for the Cardinals in 2019, going 9-14 with a 4.16 ERA, 1.22 WHIP and 144 strikeouts in 184 innings. It was a slightly disappointing campaign after his excellent 2018 campaign saw him register a 2.83 ERA and 1.07 WHIP in 200.2 innings.
Still, he was expected to be an important part of the team's 2020 rotation. That will be put on hold until the 2021 season.