Thayer, 28, is beginning his third stint with the Tampa Bay in his first Major League season. The right-hander pitched in three games during each of his two previous stints, from May 22-29 and from July 23-26. In his most recent stint with the Rays, Thayer pitched 2 1/3 scoreless innings. He is 0-1 with a 3.52 ERA in those six games.
At Durham, the right-hander was 2-5 with a team-high 17 saves and a 2.27 ERA over 51 relief appearances. Thayer has spent seven seasons in the Minor Leagues, compiling a 28-20 record, 149 saves and a 2.32 ERA.
Thayer becomes the eighth player to join the Rays since rosters expanded to 40 on Sept. 1. He joins right-handers Jeff Bennett, Wade Davis and Andy Sonnanstine, along with catcher Shawn Riggans, outfielder Fernando Perez, first baseman Chris Richard and infielder Reid Brignac.
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.