Flaherty will start Saturday's Grapefruit League opener against the Mets and likely work two innings or up to 30 pitches, Anne Rogers of MLB.com reports.
The right-hander unsurprisingly will get the call after finishing the 2019 season in dominant fashion, generating an 0.91 ERA over 15 post-All-Star-break starts. Flaherty is also the likely Opening Day starter against the Reds on March 26, although manager Mike Shildt wouldn't confirm as much when asked Wednesday.