By Lewis Gould

NFL analysts are always searching for keys to victories, which is what they are paid to do.

But the NFL changes so quickly that any reference to what happened last year is almost always meaningless.

But CBSSports.com couldn’t help itself:

For the second season in a row, the Eagles will return from their bye week and face the Arizona Cardinals.

In 2013, Chip Kelly’s Birds narrowly hung on for a 24-21 win. This year, the 5-1 Eagles will take on the 5-1 Cardinals in what should be a highly anticipated matchup. There’s a possibility the winner of this contest could get home-field advantage throughout the NFC playoffs; at the very least, the winner will be in tremendous position at the midseason mark.

Yes, there is that possibility. There is also a possibility that the winner will not get home-field advantage!

The key to this game is the match-ups, just like it always is.

For either team to win, quarterbacks Nick Foles and Carson Palmer will have to come out sharp. Foles has look erratic far too often this season, while Palmer has missed multiple games with a nerve issue. Here are three big matchups to watch, aside from the play of the quarterbacks.

WR Jeremy Maclin vs. CB Patrick Peterson

Peterson is being paid like the best cornerback in the NFL, but he isn’t playing like it.

Per Pro Football Focus, Peterson has allowed four touchdowns in 2014 without intercepting a pass. He’s been torched to the tune of a 124.9 passer rating, good for the 95th-best mark of 106 qualifiers. Peterson is one of just four cornerbacks to have allowed at least four touchdowns and a 120.0 passer rating without recording an interception.

The point is he’s been beaten badly by many wide receivers this season, and Jeremy Maclin will look to be the next.

Maclin is having himself a stellar season, especially considering he missed all of 2013 with a torn ACL. He’s 18th among receivers in yards (445), which puts him on pace for a career-high 1,200-yard season. He’s hauled in four touchdowns, making him one of just eight receivers with at least 445 yards and four scores.

And remarkably, he’s done all that without a single dropped pass. Foles hasn’t been shy in targetingMaclin; the Eagles’ sixth-year wideout ranks 13th at his position in targets (55). The problem is that too often Foles has missed an open Maclin. The completion percentage between the pair sits at just 46.6, good for 102nd among 110 QB-WR duos.

Peterson has loads of potential at cornerback, despite the frequent big plays he’s surrendered this season. There’s a good chance Peterson could pick off an errant Foles pass, but there’s an even better chance Maclin beats Peterson for six points.

DE Fletcher Cox vs. LG Ted Larsen

The Eagles have been getting relentless pressure from their front line in recent weeks, never more so than last week when the team sacked New York Giants quarterbacks Eli Manning and RyanNassib a combined eight times.

Twenty twelve first-round pick Cox has been as good of a 5-technique end as he was previously as a 3-technique tackle. This year, he’s really come into his own, starting with the fumble-return touchdown he had in Week 1 against the Jacksonville Jaguars.

For the season, Cox doesn’t have a sack yet, but he’s been putting constant pressure on opposing quarterbacks. He’s recovered two fumbles, forced one and heleads his position with 21 tackles—this all without having even one missed tackle.

Cox will line up primarily as a 3-4 end, but he will shift inside at times to accommodate pass-rushers Vinny Curry and Brandon Graham. Cox has the definitive edge over Arizona Cardinals left guard Ted Larsen, and this could make the afternoon difficult for veteran Carson Palmer.

Larsen is a replaceable left guard; PFF rates him just 70th among 79 players for the season. Larsen has already committed five penalties and allowed six quarterback hurries this season. What’s interesting is that Larsen is keeping last year’s first-round pick, Jonathan Cooper, on the bench; Cooper was picked seventh overall but couldn’t work his way into the starting lineup this season.

ILB DeMeco Ryans vs. RB Andre Ellington

Arizona Cardinals running back Andre Ellington is an underrated playmaker capable of doing damage as both a runner and receiver out of the backfield. This year, Ellington is fifth among all running backs, with 653 total yards from scrimmage.

He’s officially listed as probable for Sunday’s game against the Eagles, so expect Ellington to suit up. He isn’t the same runner as he was a year ago, and his rushing numbers are down—just 3.8 yards per carry, no games with 100 yards rushing and only one touchdown on the ground. His 1.8 yards after contact per carry (per PFF) ranks 53rd among 57 qualifying running backs.

But Ellington has thrived as a receiver. He’s fourth among backs, with 260 receiving yards. He’s caught at least four passes four separate times this season, and he’s coming off back-to-back contests with six receptions.

The Eagles are still likely to be without inside linebacker Mychal Kendricks, so Ryans will assume the role as the primary run-stopper.

Ryans is a ninth-year veteran who easily leads the team with 38 tackles and 18 stops in the running game. He will be tasked with covering Ellington on a handful of screen passes out of the backfield, and defensive coordinator Billy Davis will need to make sure Ellington doesn’t beat Ryans in this aspect.