Parker allowed two runs on one hit while walking seven over 3 2/3 innings for the win as Oakland beat Arizona, 6-5, in Cactus League action. After that, the A's top prospect was assigned to Minor League camp, and he will start the season in Triple-A Sacramento
The right-hander is 2-1 with a 3.27 ERA in four appearances this spring. Facing the team that traded him to Oakland on Dec. 9 for Trevor Cahill, Parker was aided by two double plays. The 23-year-old did not record a strikeout out and also uncorked a wild pitch.
After missing all of the 2010 season following Tommy John surgery, Parker finished 11-8 with a 3.79 ERA in 26 starts for Double-A Mobile. The Indiana native was especially sharp in the second half, posting a 2.84 ERA and continued to pitch well as Mobile won the Southern League title, permitting just two earned runs in two playoff starts.
Parker showed the potential that made him the ninth overall pick of the 2007 Draft in his Major League debut Sept. 27, tossing 5 2/3 scoreless innings against the Dodgers.
Outfielder Collin Cowgill, who was also part of the trade, was 2-for-3 with a triple and two runs scored for Oakland.