Darren Christopher O'Day was born on October 22nd 1982 in Jacksonville, Florida. The six foot four right handed side armed pitcher attended the University of Florida where he was a top pitcher.
In 2006 he was signed by the Anaheim Angels as an amateur free agent. In 2007 he shot through all levels of A ball saving a total of 21 games going 7-4 with a 2.53 ERA. The Angels were impressed and he made the 2008 club out of Spring Training as a reliever. He appeared in thirty games going 0-1 with a 4.47 ERA. In 2008 he was a Rule V draft selection of the New York Mets.
O'Day began the year with the Mets making his debut in Cincinnati in the third game of the season relieving Oliver Perez after an eight run outing. O'Day would only pitch in four games with the Mets, three innings of work overall. On April 11th he allowed two runs on three hits to the Marlins in Florida pitching just 1.1 innings. On April 22nd he was placed on waivers & was picked by the Texas Rangers.
O'Day arrived arrived with the Rangers during a game in Toronto against the Blue Jays. That night he was needed to pitch in relief but a uniform with his name had not been completed yet. With nothing else to do, he borrowed team mate Kason Gabbard's #30 and went on to pitch. Eventually his uniform with O'Day #56 was ready the next day.
He went to have a good year in Texas going 2-1 with 21 holds posting a 1.94 ERA in 64 appearances.
He remained with the Rangers for through 2011 getting to two World Series with them. In 2010 he led the staff with 72 appearances going 6-2 with 21 holds & a 2.03 ERA. In the ALCS he appeared in three games taking a loss in Game #1. In 2011 he only pitched in 16 games and was injured missing the rest of the year. He was placed on waivers in November & picked up by the Baltimore Orioles.
In 2012 he was back as a solid middle reliever going 7-1 with 15 holds a 2.28 ERA making 69 appearances for a surprising Oriole team that won an AL Wild Card spot. He pitched two innings of the AL Wild Card game as the Orioles beat the reigning AL Champion Texas Rangers. O'Day made four appearances in the ALDS pitching five scoreless hitless innings.