Rosario’s offseason began when the Red Sox claimed him from the Marlins on October 17th. Boston then traded him to Oakland for a player to be named later or cash considerations on November 28th. The A's then designated Rosario for assignment at which point the Red Sox claimed him a second time. His stay in Boston didn’t last long, however; the Cubs claimed him on December 12th.
Rosario, 27, pitched in four games for this year's Marlins team, but spent most of the season in the minor leagues. He posted a 1.99 ERA with 8.2 K/9 and 1.4 BB/9 in 31 2/3 total innings for three of Miami's affiliates.