The move makes Maness a free agent. He went 2-2 with a 3.41 ERA in 29 relief appearances this year.
Maness was drafted in 2011 by the Cardinals and made his big league debut two years later. He is 17-10 with a 3.19 ERA in 244 career relief appearances.
Maness had surgery to repair a ligament in his elbow, but it was not Tommy John surgery. Maness was eligible for arbitration before last season, but Cardinals avoided that by agreeing to a $1.4 million contract with him for 2016.
The Cardinals announced their decision Friday.