Thomas injured his left elbow while warming up in the bullpen Friday night during an eventual 10-1 loss to the Pittsburgh Pirates. Manager Jim Leyland says a postgame examination revealed inflammation in the joint. Thomas is 0-1 with a 9.00 ERA in 12 appearances this season.
The injury opens the door for the 25-year-old Furbush, who leads the International League with 55 strikeouts in 46 1-3 innings with the Mud Hens.
Though he has started at Triple-A, Leyland said Furbush will work out of the bullpen for the immediate future. Furbush was 4-3 with a 2.91 ERA in Toledo.