NFL Week 8 betting: 5 biggest storylines, including the undefeated Vikings being underdogs

Home-field advantage keeps disappearing in the NFL.

After the Dallas Cowboys won Monday night, road teams are 54-52-1 this season, according to Covers.com . The split gets even wider when the spread is involved. Road teams are 62-45 against the spread this season. Home-field advantage has been lessened through the years and through seven weeks this season, it really hasn't mattered at all.

Here are five betting storylines heading into Week 8 of the NFL season:

There's one undefeated team left in the NFL, and they're underdogs in Week 8.

The Minnesota Vikings are 6-0 and travel to face the Detroit Lions. If the Vikings feel like their great start is being disrespected, it won't get better once they see that the Lions are favored by a full field goal. The Vikings are undefeated straight up but not against the spread. They are 4-2 against the spread. Every team in the NFL has at least two losses against the spread this season.

Road teams are doing well against the spread this season and so are underdogs. A surge by underdogs the past few weeks puts them at 58-48 against the spread this season. Road underdogs are a strong 38-25 ATS (60.3%) this season, via Covers.com .

That ATS record should even out as the season goes on, but to this point it has been smart to take the points.

Throwing for 249 yards and four touchdowns in a half, when your team outscores a major division rival 35-0, is going to get some attention. Especially when it's Joe Burrow.

The Cincinnati Bengals have taken over as the betting favorites to win the AFC North, and Burrow is making his move in the MVP race after he went nuclear against the Ravens in the second half on Sunday. Josh Allen is still the big favorite with +140 odds at BetMGM, but Burrow has slid into second place at +450.

Burrow's numbers are exceptional this season and the Bengals are having team success, which gives him a chance. Voters like spreading the award around, which worked in Allen's favor two years ago and could help Burrow this time. Burrow has a very favorable schedule the next few weeks, starting with the Titans in Week 8, so he should continue to cut into Allen's lead.

The Lamar Jackson situation is making life complicated in Baltimore, and for oddsmakers too. The Ravens quarterback remained out last week with an ankle injury and Baltimore got blown out. Cincinnati covered the spread easily. We're probably in for another week of wondering if Jackson will return, which makes it tough to set a line on what is arguably the marquee game of the week.

The Ravens face the Buffalo Bills, and the Bills are 3.5-point favorites. That indicates that oddsmakers expect Jackson back, because a Tyler Huntley-led team wouldn't be that short of an underdog on the road, but the Ravens are still getting more than a field goal. That line could fluctuate a few times this week based on injury updates for Jackson.

The Rams' Super Bowl odds are fascinating. Oddsmakers don't want major exposure on the Rams if they turn it around, so after one good win against the Raiders last week Los Angeles moved back up the Super Bowl odds board. They are tied for fourth in Super Bowl odds at +1100. The only three teams with shorter odds are the 49ers, Bills and Chiefs. That's not a major move considering the Rams were fifth in the odds last week, but it's a trend that should continue.

The Rams have a soft portion of their schedule coming up, so they should improve upon their 3-4 record. And if they do, their odds will continue to get shorter. Their odds don't match the results so far this season, but there simply won't be a time in which the Rams' championship odds present fantastic value.