Torres played in 103 games with San Francisco in 2013 before having season-ending surgery on his left Achilles tendon. He has not played this year.
Torres will report to the Lowell Spinners of the New York-Penn League.
Red Sox manager John Farrell says Torres can ''give us the potential for some outfield depth.''
Torres broke into the majors in 2002 with Detroit and has played in 650 games. He has a .242 lifetime batting average with 32 homers and 174 RBIs.
There is no timetable for his debut with Boston.
Farrell says, ''Everything in his workouts right now suggest this is a worthy situation to take a look at.''