What happened: The St. Louis club returns to the diamond for the evening portion of Tuesday's split doubleheader following a 4-3 afternoon loss to Milwaukee. The front office selected the contract of left-hander Jared Shuster from Triple-A Memphis prior to the second contest. Fellow southpaw Bruce Zimmermann was designated for assignment to clear the requisite roster space.

Why it matters: Adding a fresh arm addresses the immediate pitching depth required to navigate 18 innings of baseball in a single day. Shuster provides length to Salvaging a split in the evening matchup remains critical for maintaining position in the divisional standings.

What to watch: The augmented pitching staff takes the mound under the lights to close out the extended slate. The organization will continuously monitor reliever workloads as the remainder of the series progresses.