Siani was removed from Saturday's game against the Cubs due to right oblique tightness, Derrick Goold of the St. Louis Post-Dispatch reports.
Siani had gone 0-for-3 with three strikeouts before his oblique forced him out of the game in the eighth inning. The severity of his injury remains unknown, but it's possible the Cardinals hold him out for another day or two so that he can properly recover.