Phillips will be added to the 40-man roster and assigned to Triple-A Norfolk. To make room for him, the Orioles designated Double-A Bowie pitcher Chorye Spoone for assignment.
Phillips was 1-3 with a 4.43 ERA in 33 games with Triple-A Round Rock. The former 23rd-round pick out of Sacramento City C.C. allowed 50 hits, walked 21 and struck out 38 in 44 2/3 innings.
Left-handers batted .304 against Phillips, 24, while right-handers hit .265.
Phillips went 3-2 with a 2.69 ERA in 45 minor league games last year, and 2-3 with a 1.39 ERA in 36 games in 2009.
In 213 minor league games, Phillips is 31-39 with a 4.10 ERA and 653 strikeouts in seven seasons. He's averaged 8.6 strikeouts per nine innings.
Green, signed as a minor league free agent over the winter, was batting .208 with 16 doubles, 10 homers and 46 RBIs in 87 games at Norfolk.
Spoone, 25, posted a 4.73 ERA in 19 starts between Norfolk and Bowie. He was an eighth-round pick in 2005 out of Catonsville Community College. He also pitched at Northeast High School in Pasadena.