Week 13 of the NFL season ends at Paul Brown Stadium with the Cincinnati Bengals hosting the Pittsburgh Steelers on "Monday Night Football." The Steelers are four-point favorites, down 2.5 from an open of 6.5.

The Over-Under, or total number of points Vegas thinks will be scored in the game, is 43, unchanged from where it opened.

Drama surrounding the availability of Steelers WR Antonio Brown (toe) has pushed the line down and caused the total to bounce up and down. Brown is a game-time decision and will reportedly test out his toe during warm-ups. Even if he does play, he may not be 100 percent.

Before you bet on a "Monday Night Football" game like this featuring bitter division rivals and plenty of uncertainty, you'll want to hear what Mike Tierney has to say.

Last week, he told SportsLine readers to go Under 45 on Seahawks-49ers, another divisional game. The result: just 37 points scored. Anyone who followed his advice didn't even break a sweat.

Tierney has been crushing the books for two years now, going an astonishing 44-19 on NFL Over-Under picks since the beginning of last season. And he went 4-1 last week alone.

Now, Tierney has analyzed every matchup, every trend, and every angle for the game between the Bengals and Steelers and locked in his Over-Under pick.

Tierney knows the Steelers have one of the NFL's most enviable QB/RB/WR combos with Ben Roethlisberger, Le'Veon Bell, and Brown. And even if Brown sits, Pittsburgh still has JuJu Smith-Schuster at wide receiver, who has scored in three of his last four games.

And after a sluggish start to the season, the Steelers have been hot the last two weeks, scoring a combined 71 points against the Titans and Packers. They're riding a six-game win streak.

The Bengals also have been productive offensively, averaging 25 points during their two-game win streak. They just popped 30 on the Browns, another division rival, as rookie RB Joe Mixon topped 100 yards rushing for the first time.

But just because both teams have been scoring in droves doesn't mean "Monday Night Football" goes Over, especially with a total of 43.

Monday marks the 24th meeting between Pittsburgh's Mike Tomlin and Cincinnati's Marvin Lewis. Only seven of the previous 23 games have produced at least 44 points.

And both teams rank in the top 10 in points allowed. Cincinnati has given up 33 points total over the last two weeks, while the Steelers have held opponents to 17 or fewer in five of the last six games. And Brown is a major point-scoring weapon for the Steelers. If he's limited or sits, their offense could struggle.

Tierney has evaluated all of these angles. He knows there's a huge x-factor that ultimately determines whether Bengals-Steelers goes over or under. And he's sharing it over at SportsLine.

So which side of the total should you back in Bengals-Steelers on "Monday Night Football?" Visit SportsLine now to see what big x-factor sends Steelers-Bengals over or under, all from the expert cashing 70 percent of his NFL totals picks since the start of last season.