The Blue Jays placed Thornton (elbow) on the 10-day injured list Monday, Scott Mitchell of TSN.ca reports.
Toronto recalled reliever Travis Bergen from the taxi squad to take Thornton's spot on the 28-man active roster, but the team will first require a replacement for the right-hander in the rotation Friday against the Orioles. Anthony Kay covered three innings of long relief after Thornton exited Sunday's loss to the Rays with the injury, so Kay would represent a logical option to fill the opening in the Jays' pitching schedule. Thornton is first eligible to return from the IL on Sept. 3.