Flaherty racked up 11 strikeouts and allowed an earned run on five hits over seven innings in Triple-A Memphis' 4-1 victory over Round Rock on Sunday.
Flaherty was optioned to Triple-A Memphis on Wednesday, Joe Trezza of MLB.com reports.
Flaherty was officially recalled from Triple-A Memphis prior to Opening Day.
Flaherty is expected to open the 2018 season in the Cardinals' starting rotation, Joe Trezza of MLB.com reports.
Flaherty has just an outside shot at cracking the Opening Day rotation and is likely to open at Triple-A Memphis, the Cardinals' official site reports.
Flaherty will slide into a bullpen role for the rest of the 2017 season, Derrick Goold of the St. Louis Post-Dispatch reports.
Flaherty went only two-plus innings in Tuesday's start against the Reds, allowing two runs on three hits and a walk with two strikeouts. He didn't factor into the decision.
Flaherty will start Tuesday's game against Reds and could remain in the starting rotation for the remainder of the season, Jenifer Langosch of MLB.com reports.
Flaherty (0-1) took the loss against the Reds on Wednesday, giving up three runs on four hits and two walks over 4.1 innings while striking out three.
Flaherty, who is scheduled to start Wednesday's contest against the Reds, does not have a defined innings limit as of yet, Jenifer Langosch of MLB.com reports. "The good thing about the way Jack has pitched this year is he's thrown a lot of innings without facing a lot of batters or throwing a ton of pitches because he's been so effective," general manager Michael Girsch said. "We don't have a date or a number in mind."