NFL betting: The NFL game prop with a clear edge for bettors

Finding advantage plays in sports betting isn't easy. When you do come across one, it usually doesn't stay on the board for too long. But that isn't the case with a particular NFL game prop offered by BetMGM.

The prop in question is, "Which team will be the first to use a coach's challenge?" Each team is always juiced at -115, regardless of who's on the sidelines. I've watched enough NFL games to know that some coaches have a penchant for challenging often, while others rarely toss their red flags. After wondering just how big of a potential edge this bet could carry in certain matchups, I dug up the last five years of coach's challenge data for each active head coach. My takeaway? I can't believe this prop is still being offered without adjusting the lines to reflect coaches' propensities for initiating replays, because the advantages are massive in some instances.

Before I reveal which coaches you should bet on and which you should fade, here are some fun facts:

Pittsburgh Steelers coach Mike Tomlin challenged nine calls over the course of the 2017 and 2018 seasons. None of them were overturned.

In a Week 6 loss to the Jacksonville Jaguars this year, Dolphins head coach Brian Flores challenged twice within 12 seconds. He lost both.

Seattle Seahawks coach Pete Carroll couldn't find his challenge flag in last week's loss to the Green Bay Packers, so he threw his hand warmer instead. The officials accepted it as a legal challenge.

Four coaches have yet to challenge a call this season. Three of them are first-year head coaches (David Culley, Arthur Smith and Robert Saleh). The other is Los Angeles Rams coach Sean McVay.

Four quick notes

All of the numbers are from regular season competition.

I've omitted first-year head coaches because there isn't enough of a sample size on them as of yet.

In the rare instance where a head coach missed a game, that data is still included in their totals, as it's assumed that their staff will act in a somewhat similar manner.

What I love about this prop is that its outcome relies mainly on established behavior. We have a lot of data and history to back up the correct play. Sometimes referees make calls so egregious that a coach who doesn't usually challenge is virtually forced to throw his red flag, but in the long term, you'll outrun this low variance.

Coaches to bet on

These five coaches initiate replays in more than 42% of games, on average:

Bruce Arians (Buccaneers): 50.9%

Mike Zimmer (Vikings): 50.7%

Pete Carroll (Seahawks): 43.8%

Brian Flores (Dolphins): 42.9%

John Harbaugh (Ravens): 42.5%

Harbaugh is the only one of these head honchos whose challenge percentage is higher than his success percentage (38.7%).

Coaches to fade

These five coaches initiate replays in less than 26% of games, on average:

Bill Belichick (Patriots): 25.7%

Mike McCarthy (Cowboys): 22.6%

Matt Nagy (Bears): 21.1%

Kliff Kingsbury (Cardinals): 19%

Joe Judge (Giants): 8%

A good combination to fade is coaches with a low challenge percentage but a high success rate. This means they're keeping a tight grip on their red flag and are only challenging when they feel like they have a great shot at overturning the call. Four coaches fit this bill:

Mike Vrabel (Titans): 29.3% challenge rate, 47.1% success rate

Matt Rhule (Panthers): 26.9% challenge rate, 42.9% success rate

Matt McCarthy (Cowboys): 22.6% challenge rate, 50% success rate

Andy Reid (Chiefs): 28.4% challenge rate, 52.4% success rate

Turning red into green

Any meeting between two coaches with significant challenge rate discrepancies is a great opportunity to bet this prop. Monday night's game between the Bucs and Giants, for instance, presents us with Arians (50.9%) and Judge (8%). That's as large a gap as you'll see, and you can get money down on Arians at -115 that he'll throw his red flag first.

Stats provided by Ben Austro of Football Zebras.