Knizner was recalled from Triple-A Memphis on Thursday.
Knizner is needed again as the Cardinals' backup catcher after Yadier Molina returned to the injured list with a strained thumb tendon. Knizner has gone 0-for-7 in his first two big-league games but owns a solid .277/.360/.421 slash line for Memphis this season. He'll likely be stuck on the bench behind Matt Wieters for most games until Molina returns.