Fossum spent the last three seasons with Tampa Bay, where he spent much of his tenure in the rotation before converting to the bullpen for good around midseason last year. He went 5-8 with a 7.70 ERA in 2007, allowing 109 hits -- including 15 home runs -- over 76 innings before the Rays released him in August.
The 30-year-old Fossum was in camp with the Pirates this spring, but was reassigned to the Minors near the end of Spring Training. He became a free agent when he exercised his right to decline the assignment.
Fossum joins a growing group of left-handers in Toledo while the Tigers consider their bullpen options. Clay Rapada recovered from shoulder soreness in time to open the season in the Mud Hens bullpen, and Detroit added former Cleveland southpaw Aaron Fultz a few days into the season. Macay McBride, who pitched in relief for Detroit last summer, was in the Mud Hens rotation before going on the disabled list with elbow soreness.
Jason Beck is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.