It's a tale of teams at different stages heading into 2015.

The Seahawks have been perched atop the league for the last three seasons, and are seeking a third straight Super Bowl appearance. After a crushing Super Bowl XLIX loss, Seattle reloaded and acquired Jimmy Graham in the offseason to boost their offense. However, they will also be without the services of one of their best players on the defensive side in Kam Chancellor (contract holdout).

Meanwhile, the Rams are simply trying to clinch a playoff berth for the first time since 2004. St. Louis' strength lies in a young defensive front the organization has built through the draft. It is the Rams' offense, though, that needs some time to build chemistry with a number of new faces, including quarteback Nick Foles.

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Here are three keys to the game for both the Seahawks and the Rams.

SEAHAWKS

1. Focus, focus, focus

The Rams unleashed trick plays in handing the Seahawks their third loss of the season in October. Heading into 2015, Seattle is once again the favorite to win the NFC West, while St. Louis could be a team on the rise, or floundering in mediocrity based on Jeff Fisher's track record the last three seasons. If there's anything the Seahawks need to know, all they have to do is pull up the tape from Oct. 20, 2014, and be wary of anything the Rams will try to do to pull out a win in their home opener.

2. Protect Russell Wilson

The problems centering around the offensive line in the preseason were evident. Though coach Tom Cable said his starting unit could be the best he's coached, the group is far from a finished product. On the other side, the Rams boast arguably the best defensive front in the league, headlined by Robert Quinn and Aaron Donald. If the Seahawks expect to get anything going on offense, protecting Wilson is paramount.

3. Pressure Foles

The Rams are working in two rookies along the offensive line, and a center with little starting experience (four games). And it will be Foles' first career start. The Seahawks defense is known to generate a ton of pressure, so it wouldn't be surprising to see Kris Richard's unit force Foles and the rest of the offense to make plays outside their comfort zone.

RAMS

1. Keep Foles upright

The Rams' young offensive line will be tasked with slowing down the league's best defense for three straight seasons. Foles is no stranger to seeing pressure; he was sacked 37 times from the 2013-14 seasons while in Philadelphia. If the Rams hope to have any chance of winning Week 1, they'll need to protect Foles and give him time in the pocket.

2. Attack Seahawks secondary

If Foles is able to buy time in the pocket, the Rams boast a number of weapons on the outside that have big-play potential, including Tavon Austin, Brian Quick and Stedman Bailey. The Seahawks will have three new faces in the secondary starting alongside Richard Sherman and Earl Thomas: Dion Bailey, rookie Tye Smith and offseason signee Cary Williams. Most notably, they'll be without Chancellor.

3. Wreak havoc in the backfield

There's no question the Rams' strength lies in their defensive front. But Quinn, Donald and Co. face a tall task in trying to slow down Marshawn Lynch and making Wilson uncomfortable. The Rams defensive unit will need to try generating pressure to make life uneasy for the Seahawks offensive line, and force Lynch and Wilson work.