Knizner will serve as the Cardinals' top catcher for the next few weeks while Willson Contreras spends time at designated hitter and in the outfield, John Denton of MLB.com reports.
Contreras has looked good offensively, but the Cardinals are unhappy with his performance on the defensive side and aren't going to use him much, if at all, at catcher for the near future. That opens up considerably more playing time for Knizner, though he's unlikely to do enough with it to have much fantasy value. In 197 career major-league games, he's hit .201/.287/.285 with eight homers.