Patterson, 26, was 1-1 with a 4.15 ERA pitching for Triple-A Albuquerque. He was a 29th-round pick out of Southwestern Oklahoma State University in 2010. The Dodgers might have gone with former first-round pick Zach Lee, but he pitched Sunday and would have been working on short rest.
Patterson impressed the Dodgers with his command and competitiveness in his first major league camp this spring, allowing one run in 11 2/3 innings and holding opposing batters to a .146 average.
The Dodgers took advantage of the new 26th man rule -- which allows rosters to expand by one for doubleheaders -- but had to clear room on the 40-man roster. They designated outfielder Nick Buss for assignment.