O'Day posted on his Twitter account that "it's finally time to hang 'em up."
"The mental, physical and time demands have finally outweighed my love for the game," O'Day wrote.
It's been a wild ride that I never thought I'd get to experience, but it's finally time to hang 'em up. pic.twitter.com/CewsXhgBYz— Darren O'Day (@DODay56) January 30, 2023
O'Day, 40, featured an unconventional sidearm delivery. He was 42-21 with a 2.59 ERA in 644 games, all in relief. He made his major league debut in 2008 with the Angels and pitched seven seasons, from 2012 to '18, for the Baltimore Orioles.
He posted a 4.43 ERA in 30 postseason games, including the 2010 World Series with the Texas Rangers.
O'Day also pitched for the New York Mets and New York Yankees. He pitched for the Braves in 2019-20 before returning for his second stint with the team last season. He became a free agent following the season
He set a career high with six saves for Baltimore in 2015, when he was 6-2 with a 1.52 ERA and was an American League All-Star.
The Associated Press contributed to this story.