Redmond, 27, made his only major league appearance last season in a start for the Reds, allowing four runs and seven hits, and walking five batters, in 3 1/3 innings. He was 8-11 with a 3.63 ERA in 26 games with Triple-A Gwinnett and Louisville.
Redmond is 71-61 with a 3.58 ERA in eight minor league seasons and 207 games, including 200 starts.
The Pirates selected Redmond in the 39th round of the 2004 First-Year Amateur Draft. They traded him to the Braves for Tyler Yates on March 26, 2008.
The Braves traded Redmond to the Reds for Paul Janish on July 14, 2012. The Reds designated him for assignment a week ago to make room for Manny Parra on the 40-man roster.
The Orioles, who still haven't announced the waiver claim, also must create a spot for Redmond.
Catcher Luis Exposito appears to be safe after the Orioles designated Luis Martinez earlier this week. Outfielder Trayvon Robinson is out of minor league options and on the bubble, since the Orioles have a surplus of players at his position who will be reporting to spring training next week.
The acquisition of Redmond was first reported by Darren Wolfson of 1500 ESPN (@DarrenWolfson).
Update: The Orioles designated Robinson for assignment to create room for Redmond.
Robinson, 25, was acquired from the Mariners for infielder Robert Andino on Nov. 20, 2012. He batted .215/.272/.330 in 90 major league games over the past two seasons with Seattle.
Also, the Orioles announced that Martinez cleared waivers and was outrighted to Triple-A Norfolk. He will report to spring training as a non-roster invitee.