Week 1 of the NFL season often causes overreactions, even in the betting market. The hard part is trying to decipher what from Week 1 is worth a strong reaction, and what isn't. As a result, the early part of the season is susceptible to major line movement. Oddsmakers' power rankings of teams aren't yet complete and sharp action can have a stronger influence than usual.

We've seen some early line movement ahead of Week 2, some of it reacting to how good some teams looked while other movements seem to be reacting how bad some teams looked. Let's take a look at the largest line movements ahead of Week 2.

Are bettors fading the 49ers?

The San Francisco 49ers lost outright as a 6.5-point favorite in Chicago last weekend. For Week 2, they were installed as a 10-point favorite in their home opener against the Seattle Seahawks. That line quickly moved to 9.5 points after Monday Night Football, where the Seahawks looked somewhat competitive, which many didn't expect.

As action has trickled in, the line has moved even further in the direction of the Seahawks. Currently, Seattle is just an 8.5-point underdog at BetMGM.

It's tough to make a judgement on San Francisco after its opener since the game was played in a monsoon. The questions are obvious with their quarterback situation. While Trey Lance didn't do anything to alleviate those concerns in the opener, it feels a little early too rush to judgement. Of course, the presence of Jimmy Garoppolo as the backup quarterback will keep the heat on Lance, even if it's not totally fair.

As for Seattle, a lot of people expected them to be in the running for the first overall pick in next year's draft. They quieted those discussions with a win over Denver on Monday night as a 6.5-point underdog. It'll be interesting to see how Seattle looks in its second game. Will Geno Smith remain solid all season and will the Seahawks be as good when they aren't looking to stick it to their former quarterback?

Market thinks Arizona might just be bad

The Arizona Cardinals opened as a 3-point home underdog over the summer against the Kansas City Chiefs in Week 1. By kickoff, that spread ballooned out to 6.5 points. The game wasn't close as the Chiefs won by a score of 44-21. Things are unfolding similarly this week.

Arizona opened as a 3.5-point road underdog against the Las Vegas Raiders on Sunday. By Monday morning, the Cardinals were a 5.5-point underdog, which is where the spread sits currently. It's worth noting that this is the second straight week the market reacted strongly against Arizona.

There were a lot of questions surrounding the Cardinals entering the season. Last season was a tale of two teams; an elite one to start the year and a highly questionable one to end the season. Early returns in Week 1 against the Chiefs were not great. The market seems to expect that to continue as the Raiders have become bigger favorites.

Other line movements

What other games have seen line movement over the course of the week?

• For Thursday night, the Chargers opened as just 3-point underdogs. However, the Chiefs are now 4.5-point favorites.

• The biggest movement of the week comes in the total for the Jets-Browns game. It opened at 42.5-points, but it's currently down all the way to 39.5 points. It's the first total below 40 of the season, which is a rarity in the modern NFL. Of course, it's hard to expect fireworks when the quarterback matchup features Joe Flacco and Jacoby Brissett.

• Philadelphia opened as a 3-point home favorite against the Vikings, but that line has come off the key number of three. Currently, the Vikings are a 2-point underdog.

• The Saints opened as a 3-point home underdog against the Tampa Bay Buccaneers, but that number has dipped under a field goal as the Saints are getting just 2.5 points now. Tom Brady has struggled against the Saints in the regular season as a member of Tampa Bay. It's worth keeping an eye on the status of Tampa Bay's receivers, as Chris Godwin, Mike Evans and Julio Jones all did not practice on Thursday.