O'Day announced Monday via his personal Twitter account that he has retired from professional baseball.
O'Day (calf/toe) was transferred from the 15-day injured list to the 60-day injured list Thursday.
O'Day (calf) had his rehab assignment shut down after he sustained a right big toe injury at Triple-A Gwinnett on Tuesday.
Atlanta transferred O'Day's (calf) rehab assignment from High-A Rome to Triple-A Gwinnett on Tuesday.
O'Day (calf) will begin a rehab assignment at High-A Rome on Friday.
Atlanta placed O'Day on the 15-day injured list Wednesday with a strained left calf muscle.
O'Day (1-0) earned the win in relief Friday against the Padres after tossing a scoreless inning with two strikeouts.
O'Day had his contract selected by Atlanta on Sunday.