Week 8 of the NFL season starts at M&T Bank Stadium with "Thursday Night Football" between the Baltimore Ravens and Miami Dolphins.

The Ravens are three-point favorites, while the over-under, or total number of points Vegas thinks will be scored, is a low 37.5, unchanged from where it opened.

Before you make any bets on Dolphins-Ravens, you'll want to hear what Mike "Top Dog" Tierney has to say.

In prime time in Week 6, Tierney told SportsLine readers to go under 40 on Giants-Broncos, a game he knew featured the league's top defense and an offense that would struggle. The result: Giants 23, Broncos 10, and the easiest under ever.

Amazingly, it also helped improve Tierney's over-under record to 12-6 this season after he went a blistering 22-9 last year. He has a gift for picking NFL totals, and anyone who has followed his picks is up big.

Tierney knows that 37.5 would make Dolphins-Ravens tied for the lowest total of the season. There have been 13 over-unders below 40 this season and, remarkably, the Ravens have been involved in four of them. This game could feature two tired defenses and a low total for them to hit.

And "Thursday Night Football" has largely been high scoring this year, with half the games going over 50 points. Matt Moore led the Dolphins to 17 points in the fourth quarter alone last week against the Jets and threw for 188 yards and two touchdowns.

But just because the over-under is uniquely low doesn't mean the game goes over.

Dolphins quarterback Jay Cutler (ribs) is likely out and tackle Laremy Tunsil (knee) is banged up. As for the Ravens, Joe Flacco is flailing without many weapons and his passer rating at 70.

Both teams rank in the bottom third of the NFL in scoring, and Baltimore needed a buzzer-beating touchdown Sunday to take its game over 37.5. It was the Ravens' first touchdown in nearly 11 full quarters.

In addition, both teams' stars have disappointed this season. Dolphins running back Jay Ajayi has yet to score while Flacco has more interceptions (eight) than touchdowns (five).

Tierney is leaning on the Ravens to cover, but what about the over-under, which he has made his name picking?

He knows there's a huge x-factor that ultimately determines whether Dolphins-Ravens on "Thursday Night Football" goes over or under. And he's sharing it over at SportsLine.

So which side should you back in Dolphins-Ravens on Thursday night? And does this game go over or under? Visit SportsLine now to see what big x-factor sends Dolphins-Ravens over or under, and see which side of the total you need to be all over, all from the expert who is blistering hot on NFL total plays.