According to a report in the St. Louis Post-Dispatch, the Cardinals have a tentative agreement with Miller to be the team's left-handed specialist.
Miller went 2-0 with a 4.19 ERA in 68 relief appearances with the Rays this past season, but he had a 1.78 ERA against left-handed hitters and held them to a .209 batting average. In 10 big league seasons, including 519 appearances, Miller is 14-14 with a 4.43 ERA.
The 35-year-old made $2 million last season, which includes his $400,000 buyout, and he's joining his seventh big league team.
Cardinals relievers were 11th in the National League last season with a 4.20 ERA. The club felt pressured to sign a lefty reliever once Jeremy Affeldt signed with the Giants and Will Ohman received an offer to remain in Atlanta, the report said.
The club is expected to add at least one more left-hander to its bullpen.
Mike Scarr is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.