Although on the 40-man roster, Ravin has not pitched for the Dodgers this season, as he broke his non-pitching arm in a car accident.
In a statement, Ravin claimed his positive test was caused by supplements he took after dealing with illnesses during spring training.
"During 2016 spring training, I came down with a severe case of intestinal flu and strep throat. I was put on antibiotics and lost a total of 20 pounds in less than seven days," Ravin said Monday in a statement. "To try and speed up my recovery, I took some supplements that I thought would help. Unfortunately, I was not as careful as I should have been and one of the supplements contained a banned substance.
"I later learned that the substance showed up in a regular drug test done of me during 2016 spring training. This has been a very painful lesson for me. I have always tried to avoid doing anything in violation of the system and I take full responsibility for the consequences of my actions and my bad judgment. So, I have decided to accept the suspension and continue my ultimate goal to be able to pitch again in the major leagues."
In 2015, Ravin was 2-1 over 9 1/3 innings for the Dodgers. He posted a 6.75 ERA with 12 strikeouts and four walks.
The Southern California native appeared in nine games last season and made his major league debut at age 27. He was a fifth-round draft pick by the Cincinnati Reds in 2006, and he pitched in the minor leagues for 10 seasons.
Ravin becomes the latest player suspended by the league after a positive test.
Reigning National League batting champion Dee Gordon of the Miami Marlins and Toronto Blue Jays outfielder Chris Colabello have each been suspended 80 games this season. New York Mets reliever Jenrry Mejia was banned for life the past offseason, after a third positive test.
Information from ESPN.com Dodgers reporter Doug Padilla contributed to this report.