Uehara will be introduced to the media at a noon news conference on Wednesday, and his signing gives the Orioles a veteran starter to slot behind staff ace Jeremy Guthrie.
Uehara, who signed a two-year contract, was 112-62 with a 3.01 ERA in 10 seasons for the Yomiuri Giants. The right-hander has struck out 1,376 batters and walked just 206 batters in his career, and his presence should help steady a staff that has led the league in walks in each of the past two seasons.
Uehara will turn 34 shortly before the season begins, and he's one of just three pitchers -- along with Masaki Saito and Kazumi Saito -- who have won Japan's Sawamura Award more than once over the past 20 years. Other notable winners include recent Braves signee Kenshin Kawakami, Hideo Nomo, Daisuke Matsuzaka, Kei Igawa and Yu Darvish.
Baltimore is expected to seek more rotation help, and right now Guthrie and Uehara are the only surefire rotation members on the roster. The Orioles also signed Mark Hendrickson this offseason, but manager Dave Trembley said recently that he'd prefer to use the southpaw in a relief role and as a situational starter.
Uehara, an eight-time All-Star in his native land, has also pitched in relief during his career. He saved 32 games and was named to the All-Star Game as a reliever in 2007, but the Orioles see him exclusively as a starter.
Spencer Fordin is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.