To take Lobstein's place on the 40-man roster, the Orioles added outfielder Drew Stubbs, who had been waived by Texas on Monday and was claimed by Baltimore on Wednesday.
Stubbs was batting .259 with three home runs and six RBIs with eight steals in 39 games with the Atlanta Braves and Texas this season. He can play all three outfield positions and is a good defensive player. He is expected to join the team Friday.
Phillips, 29, has spent the entire 2016 season with Triple-A Norfolk, where he went 9-3 with one save and a 4.45 ERA in 49 relief appearances.
Phillips made his major-league debut with the Orioles in 2011 and had a 1.12 ERA 10 games that season. Phillips made his last appearance in a major-league game with the Marlins on September 15, 2013.
He will not be added to Pittsburgh's 40-man roster and will be assigned to Triple-A Indianapolis.
Lobstein was 2-0 with a 3.96 ERA in 25 innings for the Pirates this season.