What is line movement? Well, during the NFL season, bookmakers usually post a spread with a total as early as possible so they can begin taking bets. For Week 13, these lines were posted as early as Sunday night and have since been adjusted. These lines are adjusted in the following hours and days due to transactions, injuries, weather reports, large bets on one side -- any number of things.

The Denver Broncos are 3.5-point road favorites against the Jacksonville Jaguars. The Broncos were as high as five-point favorites earlier this week, but then came the news that quarterback Trevor Siemian is questionable to play. That line movement moves in Jacksonville's favor.

Another reason to like the Jacksonville D/ST is the dwindling game total. The game opened at a low total of 43 and has already plummeted to 40.5 points.

Back in March, I wrote about how line movement affects defensive performances, and when the total was between 39 and 42 points in 2015, the defenses involved averaged 8.06 fantasy points per game. In that same year, if the total dropped 2.5 points or more throughout the week, defenses involved scored an average of 8.59 fantasy points per game.

While the Denver D/ST is favored and makes for a terrific play in this spot, they are priced at $5,000 on FanDuel, the second highest among all defenses. The Jags defense is priced at $4,000, tied for the lowest among all defenses on the slate. They certainly are a risk, but if you are looking to go cheap on a defense, you really can't do worse.