Rosario pitched in only four games for the Miami Marlins this season, allowing six earned across three innings for an ERA of 18.00. Rosario did flash some potential in the minors though logging a 1.99 ERA with 8.2 K/9 for three different affiliates throughout the 2012 season.
The Giants' acquisition of Rosario completes his epic cross-country journey this offseason as he's now gone from Miami to Boston to Oakland back to Boston to Chicago to San Francisco in about two months time. If the 27 year old is able to stick in the Bay, he'll be expected to fight for a bullpen spot. And with competition shaping up to be Chad Gaudin, Omar Javier, Eric Hacker and Fabio Castillo, there's certainly a chance that Rosario makes it out of Spring Training alive.