Eight games into the 2015 season, Seahawks opponents have completed only one touchdown pass to a wide receiver, and that came from Packers quarterback Aaron Rodgers, who extended the play with his legs, then threaded a laser between All-Pro defensive backs Earl Thomas and Richard Sherman to hit James Jones in the end zone, a throw few, if any, other quarterbacks would have the audacity to even attempt, let alone successfully execute.

The Arizona Cardinals, meanwhile, come into Sunday night's NFC West showdown against Seattle thriving when Carson Palmer throws to his top receivers, Larry Fitzgerald, Michael Floyd and John Brown, who have combined to catch 112 passes for 1,587 yards and 13 touchdowns.

And that brings us to our three key matchups for Sunday night's game at CenturyLink Field between the first-place Cardinals and the Seahawks, who are hoping to once again overtake Arizona in the standings with a second half surge.

1. Carson Palmer and the Cardinals' big-play passing attack against the Seahawks pass defense.

Not everything has gone well for the Seahawks' defense this season—as is evident in the production of opposing tight ends, which has been a combination of good execution by good players and a few communication errors—but for the most part the pass defense has done the No. 1 thing Pete Carroll asks of a defense: take away big plays, and long touchdowns in particular.

Arguably no player is more important to Seattle's defense than free safety Earl Thomas, not because of the plays Thomas makes, but because of the ones opposing offenses don't make.

"It's a crucial aspect," Carroll said last year. "He plays a lot of deep-middle responsibility, and people don't appreciate that (opponents) don't throw post routes for touchdowns on us, and how many times they don't throw seam routes for touchdowns on us. That happens all the time every single day in football, and we're great at taking care of that."

The way the Seahawks ask Thomas, Kam Chancellor and their cornerbacks to play, there will be room for short pass completions in the middle of the field—Peyton Manning set a Super Bowl record for pass completions against Seattle, yet his offense managed a single touchdown in a blowout loss—but getting beat deep is a no-no in a Carroll defense.

"In our defensive scheme we are extraordinarily tied to that principal," Carroll said earlier this season. "If you give up long touchdown plays, you're not a very good defense. It doesn't matter what you do, or how hard you hit or whatever, so it all begins there. That's the first aspect of playing defense, you can't give up easy plays, so it just begins there. How much do we speak about it and try to make sense of that? As much as we can and as much as need be, and we're very lucky and fortunate that our guys on the back end have really understood that. Earl has been a tremendous advocate of the philosophy, as has Richard and Kam, and Cary (Williams) is really tuned in."

Which brings us to the Arizona Cardinals, who under head coach Bruce Arians have one of the most aggressive passing attacks in the NFL, one that nobody is expecting to go into a shell against the Legion of Boom.

"We attack, in every situation," Palmer said. "… We're going to spread you out, we're going to take shots, and we're going to be aggressive."

So far this season, the Cardinals have completed 37 passes of 20 or more yards, the third most in the NFL, and Palmer is averaging a league-best 9.1 yard per pass attempt. The Seahawks meanwhile, started off the season by uncharacteristically giving up 11 completions of 20-plus yards in their first two games, but have allowed only 14 in six games since then, looking more like the defense that allowed the fewest such plays in each of the previous two seasons (30 in 2013, 32 last year).

And as is always the case, stopping a potent passing attack isn't just the job of Seattle's secondary. No matter how talented Seattle's defensive backs are, if Palmer has long enough to operate, he's going to complete a lot of passes, which is where the pass rush comes into play. Seattle's front seven, and ends Cliff Avril and Michael Bennett in particular, have been good at generating pressure this season, even if it hasn't always shown up in the form of sacks, and will need to make Palmer uncomfortable Sunday for the defense to be at its best.

"It's very important," Avril said. "Any time they throw the ball, (the pass rush) is very important, but a team that likes to go down the field gives you a little more time to pass rush and make that last effort to get after the quarterback. You put pressure in any quarterbacks face, or up the middle where they feel guys at their feet, or hitting them a split second after they throw the ball, they feel that, and they start to think about it. So you definitely want to get after him as much as possible."

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2. Marshawn Lynch vs. Arizona's run defense.

Overall this season, the Cardinals have been very good against the run, allowing 90.1 rushing yards per game, which ranks fourth in the league. In their two losses, however, the Cardinals allowed a total of 305 rushing yards to Pittsburgh and St. Louis, showing that a strong rushing attack can succeed against Arizona's defense.

The Seahawks haven't quite lived up to last year's franchise-record rushing standard, but they are still third in league with 139.5 yards per game. While Marshawn Lynch is listed as questionable because of an abdominal injury that showed up late in the week, Carroll sounded optimistic that the Pro-Bowl back will play. And whether it is Lynch or Thomas Rawls carrying the load, the Seahawks need to establish a running game to keep an aggressive Cardinals pass rush honest.  

"It is important," Carroll said. "It is important, and they're good against the run too. They make it hard because of the way they stunt and all of that. We see them pressuring almost half the time so we're going to, we don't want to have to allow them to come after us with all that in the passing game, so running the football is really important. It's always important to us anyways, but it is important against this scheme."

The Seahawks have had success running on Arizona, most notably rushing for 267 yards on 34 carries in their last meeting, and in case anyone had forgotten, Lynch did do this the last time he faced the Cardinals:

3. Cardinals ball security vs. a Seahawks defense that feels like its due for some turnovers.

The Cardinals have two games in which they didn't turn the ball over and two more with just one giveaway, so it's not fair to say turnovers have been a consistent problem, but there have been games when the turnovers come in bunches for Arizona. In both losses, Arizona gave the ball away three times, and the Cardinals had four turnovers in their most recent game, necessitating a big second-half comeback for a win over Cleveland.

The Seahawks, meanwhile, have not been forcing turnovers at the high rate they are used to, and have just nine takeaways in eight games and none in their past two. Perhaps most surprising is the fact that Seattle has only three interceptions.

"It's always really frustrating," Carroll said. "There's a couple of times in our years that we've seen it like this, and it's like we say, they come in bunches. I can't imagine that it can continue to happen, because the rush is effective, and we are getting the kind of speed rush that we want in effect. Let's get some games at home, see what happens here, see if we can't get it cranked up a little bit."