Arizona Cardinals quarterback Drew Stanton suffered a partial tear of his ACL, in addition to a sprained MCL in the same right knee, and medical sources say a realistic return to action should occur in "about four weeks."

That time frame, based on successful therapy and healing, gives him a realistic chance of returning for the NFC playoffs, according to sources, especially if the Cardinals can secure a first-round bye.

Stanton suffered a Grade 2 sprain, or a partial tear, of the ACL which had been repaired in 2007, sources said. Initially, the team feared he had suffered full tear in Thursday's win in St. Louis but an MRI alleviated those concerns.

The team has said Stanton is "week-to-week" and one source said "everybody is different" and cautioned about putting a specific time on his return.

The MCL sprain is the more painful of the two injuries, a source said. A knee brace will provide support for stability caused by the partially torn ACL if and when Stanton returns.

The Cardinals can clinch a postseason spot Sunday if the Cowboys and Eagles game does not end in a tie. The Cardinals have the NFC's best record at 11-3 and are still aiming for a first-round playoff bye.

They have two remaining regular-season games, at home against the Seahawks next Sunday and then finishing the season on the road against the 49ers.

Ryan Lindley finished the game for Stanton in Thursday night's win in St. Louis and he is expected to start against Seattle.