Carson Palmer, who plays quarterback for the Arizona Cardinals, was carted off to the locker room during the fourth quarter of the game on Sunday against the St. Louis Rams.

According to Yahoo Sports, Palmer appeared to have hurt his leg while he was trying to avoid a sack. Fans observed that the quarterback was still able to walk off the field but he was immediately taken to the locker room after the accident.

It is believed that he will miss a few games due to his injury. It can be remembered that he was not able to play for three games in the season after he damaged a nerve in his shoulder.

A similar report of NFL.com revealed that the left-knee injury of Palmer is believed by the Cardinals to be torn ACL. Reports said that he already suffered the same injury in 2006 and caused severe damage to his ligament.

Coach Bruce Arians said they are not yet sure of the exact prognosis of their quarterback, noting that he still needs to undergo more tests to confirm his real condition.

Palmer has just recently signed a three-year extension with the Cardinals worth $50 million with $20 million guaranteed.

After leaving the game, Palmer was replaced by backup quarterback Drew Stanton, NFL.com reported. It added that the latter might take the role for quite a while since the team would still wait for Palmer's recovery.

Stanton was able to connect to rookie John Brown who made a 48-yeard touchdown, which gave the lead to the Cardinals and earned a 31-14 victory for the team. NFL.com said that Stanton may lack "NFL-starter quality" but he has shown his willingness to make things happen for his team.

ESPN discussed in a report that the Cardinals will have to rely on Stanton especially if Palmer will be out for a long term.

"The further you are removed, the harder it is to get back into sync. Things happen quickly out there. You have to trust your eyes. That's the biggest thing I learned from my three starts," Stanton told ESPN.

His teammates said that Stanton is someone they can rely on during the game since he is known to step up and do the job assigned to him.

Brown said in the ESPN article said that team remains confident in the performance of the remaining players. "It's just like Carson never left," he added.

Another Cardinal Patrick Peterson said the team is already aware of what they need to do to win the games. "It goes to show the leadership we have in this locker room. We faced a lot of adversity. We let these games slip away last year, getting into the fourth quarter down. We didn't know how to dig out of the hole. Now we understand how to win ballgames. How to finish out the fourth quarter. That's what it's all about," Peterson said.