ST. LOUIS -- It all comes down to this.
The St. Louis Rams will play the Arizona Cardinals on Sunday at University of Phoenix Stadium with both teams trying to get closer to a berth in the playoffs.
At 7-5, the Cardinals are close. They trail Carolina (9-3) and San Francisco (8-4) but are still in the hunt and will finish the regular season by hosting the 49ers.
At 5-7, the Rams would likely need to win out to qualify after last week's loss in San Francisco. The remaining regular season schedule isn't favorable for St. Louis, but there's still a slim chance.
Here are three things to keep an eye on this Sunday when the Rams travel to Arizona:
CARSON PALMER
It seems like forever ago, but the Rams beat the Cardinals 27-24 in the season opener on Sept. 8 as Sam Bradford threw for 299 yards and two touchdowns and tight end Jared Cook had seven catches for 141 yards and two scores.
Carson Palmer completed 26 of 40 passes for 327 yards and two touchdowns in his Cardinals' debut, which was arguably his best performance in the team's first nine games.
For the past three weeks, Palmer has been at the top of his game.
He threw for 419 yards and two touchdowns in a win at Jacksonville. He had 314 yards passing and two touchdowns in a win against Indianapolis. He then had 302 yards and three touchdowns, but also two interceptions, in a 24-21 loss at Philadelphia last week.
Palmer has 19 touchdowns and 17 interceptions for the season, but has seven touchdowns and only two interceptions the past three weeks. Those are the kind of numbers that will help the Cardinals in their push for a playoff spot.
But Arizona coach Bruce Arians said Palmer, who has been limited in practice by a right elbow injury, is a game-time decision for Sunday but expects the quarterback to be ready to go.
If Palmer can't, the backup quarterback is Drew Stanton, who hasn't thrown a pass in the regular season since Dec. 19, 2010, when he was with the Detroit Lions.
ARIZONA RUN DEFENSE
This week will be the biggest test the St. Louis running game has faced. The Cardinals rank fourth in the NFL in rushing defense, allowing just 83.3 yards per game. Only the Jets (77.0), Panthers (80.3) and Lions (82.7) allow less.
Thanks to rookie revelation Zac Stacy, the Rams have racked up at least 114 yards rushing in each of their last five games and are averaging 174.4 yards rushing over that five-game stretch -- the most in the NFL in that time.
Quarterback Kellen Clemens has done an admirable job taking over since Bradford suffered his season-ending knee injury. He is 2-3 as a starter, has completed 51.7 percent of his passes for 1,019 yards, five touchdowns and three interceptions, with a passer rating of 77.3.
If he qualified, Clemens' passer rating would rank 31st in the NFL -- right behind Joe Flacco (78.5), Christian Ponder (77.9) and Matt Schaub (77.6) and ahead of Chad Henne (74.9) and Eli Manning (74.3).
Clemens has done a good enough job to help the Rams win games, but it's obvious this offense is not able to spread it out and throw darts all over the field. When they are able to pound the ball with Stacy (696 yards rushing, four touchdowns), it softens up opposing defenses for the passing game.
The Rams will need to do that on Sunday to have a chance.
RAMS OFFENSIVE LINE
This isn't sexy, of course, but the Rams offensive line will be an area to watch on Sunday. It's been a game of musical chairs in recent weeks because of injuries but has still been a mostly successful unit.
Tim Barnes will make his first NFL start at center after Scott Wells suffered his season-ending broken fibula against the 49ers.
Left tackle Jake Long was a full participant in practice on Friday and is officially "probable" for Sunday's game after suffering a concussion in the second half against San Francisco. He has started all 12 games this season, as has left guard Chris Williams.
Also probable is right guard Harvey Dahl, who is set to return soon from a knee injury he suffered against the Seahawks.
You can follow Nate Latsch on Twitter (@natelatsch) or email him at natelatsch@gmail.com.
