Rosario changes teams for fourth time since October
The team announced the move on Wednesday.
Rosario has played in parts of three seasons with the Miami Marlins, allowing 13 earned runs in 7 2-3 innings over 10 relief appearances.
Rosario was claimed off waivers by Boston from the Marlins in October and got traded to Oakland last month. The Red Sox acquired him again off waivers from Oakland on Monday.