O'Day (calf) will begin a rehab assignment at High-A Rome on Friday.
O'Day has been on the injured list since July 13 due to a left calf strain, but his rehab assignment should be the final step in his recovery process. It wouldn't be surprising to see the right-hander require several appearances in the minors since he's been sidelined nearly a month, but he should be in consideration to rejoin Atlanta's bullpen soon.