The Orioles have designated the veteran righthander for assignment and purchased the contract of lefthander John Parrish from Double-A Bowie of the Eastern League.
Helling, a former 20-game winner with the Texas Rangers, was signed as a minor league free agent by the Orioles on Feb. 10. He earned a spot on the 25-man roster in spring training, but was just 7-8 with a 5.71 ERA in 24 starts this season.
Parrish missed all of last season because of a torn ACL in his right knee. At Bowie, he posted a record of 3-3 with an ERA of 2.00 and six saves.
Parrish has pitched in part of two seasons for the Orioles, going 3-6 with a 6.79 ERA in 24 appearances, including nine starts.
In Friday night's 6-4 loss to the New York Yankees, Parrish pitched one-third of an inning and walked one batter.