Mautz will be available out of the bullpen for Monday's game in Milwaukee, Derrick Goold of the St. Louis Post-Dispatch reports.
Mautz had been slated to start Sunday's game in Cincinnati in what would've been his major-league debut, but that contest got rained out. The Cardinals have opted to keep Mautz on the active roster for the time being, though Ryan Fernandez is on the taxi squad and could replace Mautz as soon as Tuesday.