Cardinals quarterback Carson Palmer has torn ACL

Arizona Cardinals quarterback Carson Palmer sustained a torn ACL in Sunday's game against the St. Louis Rams and will be placed on injured reserve.

Arizona Cardinals quarterback Carson Palmer sustained a torn ACL in Sunday's game against the St. Louis Rams and will be placed on injured reserve, the Cardinals announced Monday. 

Palmer was carted off the field with a left knee injury that was believed to be an ACL tear. 

• What's next for Carson Palmer after re-injuring knee

According to AZCentral's Kent Somers, Palmer said he felt a pop when the injury occurred and knew it was his last play of the season.

Palmer said he cried like a baby last night. Hadn't cried since Chris Henry passed away.

— Kent Somers (@kentsomers) November 10, 2014

The 34-year-old said he will play football again and hopes it will be in Arizona, but understands the Cardinals have to do what's best for them as a business. On Friday, Palmer agreed to a three-year, $50 million extension with Arizona, which ESPN's Chris Mortensen reports is only guaranteed through next season.

Palmer previously tore the same ACL in 2006. He said he hasn't decided who will do his surgery, but won't use cadaver tendon for it like he did in 2006. 

• MMQB: Don't count out the Cardinals yet

Palmer was replaced in the game by backup quarterback Drew Stanton. The Cardinals went on to win 31-14 to improve to 8-1 on the season. Palmer was 6-0 as a starter in 2014 and previously missed three games due to a nerve issue. 

Arizona hosts the Detroit Lions on Sunday. 

- Molly Geary