Rosario is returning to the Red Sox, who selected the right-hander off waivers from the Miami Marlins in Oct. Boston then dealt him to the Athletics for a player to be named later, who turned out to be right-hander Graham Godfrey.
After acquiring Rosario from the Red Sox on Nov. 28, the A’s designated him for assignment two days later to make room on their roster for right-hander Chris Resop.
Rosario appeared in only four games with the Marlins last season, allowing six runs on eight hits with two strikeouts over three innings. The 27-year-old spent a majority of the 2012 campaign in the minors with Miami’s high-, Double- and Triple-A squads. Combined between his three stops he posted an ERA of 1.99 with 8.2 strikeouts and 1.4 walks per nine innings.
Over seven seasons at the minor league level Rosario has maintained an ERA of 3.48 with 9.3 strikeouts and 2.1 walks per nine innings. He’s allowed 13 runs over 7 2/3 innings in the majors.