Per NFL Network's Ian Rapoport, Stanton had been playing with "a thread" of an ACL before it finally gave out.
Rapoport added Stanton is not planning to have surgery because he's learned how to manage the situation.
Stanton missed five games with a sprained right knee suffered in Week 10 against the Seahawks. He was replaced by Blaine Gabbert until Stanton returned against the New York Giants in Week 16.
Stanton previously sprained the MCL in his right knee late in the 2014 season.
In four starts this season, Stanton threw for 828 yards and six touchdowns with four interceptions. The Cardinals went 3-1 with him under center.
The 33-year-old is scheduled to become a free agent this offseason. He has been with the Cardinals for the past four years.