With reliever/spot starter Joe Kelly also unable to pitch out of the 'pen on Thursday, the Cards needed to add someone who could offer help immediately. Siegrist, the sixth pitcher to be added to the roster since May 26, was already on the 40-man roster. He most recently pitched on Monday.
"It's kind of a surreal feeling to finally get here," Siegrist said of stepping into the Cardinals' clubhouse for the first time. "I know most of these guys from Spring Training. I'm just excited. Just ready to get going."
Siegrist, 23, was named the organization's Minor League Pitcher of the Month for May. He made his first 13 appearances of the season in Double-A before earning a late-May promotion to Memphis. Combined, Siegrist allowed six earned runs, 11 hits and 10 walks in 27 2/3 innings. He also recorded 44 strikeouts.
"I've just been consistent with my fastball, not walking a lot of guys," Seigrist said. "Trying to keep that up."
Siegrist will become the second left-hander in the Cardinals' bullpen, joining lefty specialist Randy Choate. The Cincinnati Reds, this weekend's opponent, feature four lefties in their regular lineup.
"A lot of things went into the decision. Partly the fact that he's been one of the best pitches we have in our Minor Leagues, hence the award he was given," manager Mike Matheny said. "But there's no question there's some lefties in that [Reds] lineup that we wouldn't mind having an extra left-hander around for."
Siegrist is also St. Louis' eighth rookie pitcher to make his debut on the Redbirds' Major League roster this season. Despite all the shuffling, a Cards team that has had 22 pitchers on the roster still leads the Majors with a 3.10 ERA.
• Chris Carpenter threw off the mound Thursday to live batters for a second time in his rehab.
• Fernando Salas (right shoulder inflammation) has been cleared to play catch and take batting practice.
• The Cardinals' game against the Cubs on June 17 has been picked up by ESPN for a national telecast. First pitch has been moved up to 6:05 p.m. CT.
Chad Thornburg is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.