Manager Buck Showalter said Flaherty would "probably stay with the team today, and he could go out on a rehab not before Sunday."
Flaherty has been on the disabled list since Wednesday due to a bacterial infection that caused severe swelling in his tonsils. After enduring a period where it was difficult to even breathe, Flaherty started on antibiotics, which he said have had a significant impact.
On Friday, Flaherty said he felt his energy level was fine, but was still waiting for the swelling to fully subside.
A Rule 5 Draft selection who has taken on a utility role with the O's, Flaherty has hit .205 with four home runs and 11 RBIs in 60 games and 117 at-bats this season.