The 35-year-old Shields was a free agent after two injury-plagued seasons. He retired Friday as only the third player with at least 10 seasons to spend his entire career with the Angels.
Shields established himself in the bullpen in 2002, when the Angels won their only World Series. In his final 38 relief appearances he allowed just seven earned runs.
He gave starting a try in 2003 but returned to the bullpen in '04, setting up Troy Percival and Francisco Rodriguez as the Angels won five of six AL West titles.
Shields finished 46-44 with a 3.18 ERA.