The deal was announced Wednesday.
The 27-year-old Caminero is 0-1 with a 5.49 ERA in 19 career appearances with the Marlins. He allowed eight runs in 6 2-3 innings with Miami last season. The 6-foot-4, 250-pound Caminero went 4-1 with 10 saves, a 4.86 ERA and 79 strikeouts in 42 relief appearances with Triple-A New Orleans in 2014.
Caminero fills out the final spot on Pittsburgh's 40-man rotation. The Pirates report for spring training in two weeks.