The Denver Broncos know what’s coming Sunday.

Their defense’s season-long weakness, defending the run, has prevented them from matching the performance of the 2015 championship team. Now the Broncos’ leaky run defense will get one of its biggest tests Sunday at Tennessee, which features a run-heavy offense and a dual-threat quarterback.

In a league full of fantasy football numbers, Tennessee‘s offense is more old-school, with a smash-mouth running game headed by power backs DeMarco Murray and Derrick Henry, plus elusive quarterback Marcus Mariota.

It’s a matchup heavily slanted in favor of the Titans’ third-ranked rushing offense, which is why the Broncos have focused so much on run defense in preparation this week.

“It doesn’t matter what they do in the run game,” said Broncos safety T.J. Ward, who will probably play closer to the line of scrimmage than he normally does to try to help slow Murray and Mariota. “We’ve got to take care of what’s going on in-house.”

Taking care of in-house problems includes self-evaluation in determining which teams have exposed in the Broncos’ 28th-ranked run defense. The numbers are borderline embarrassing for a Super Bowl champion that was built on defense. In seven of the Broncos’ 12 games this season, opponents have rushed for more than 120 yards.

The problems have been multifaceted. Free-agency departures and injuries have thinned the talent. Denver’s inside linebackers have struggled to shed blocks and plug the running game at times. Occasional poor tackling in the secondary and overaggressiveness on the edge has allowed running backs and quarterbacks to get big plays to the outside.

So what’s the game plan against the Titans, the best running team they’ve faced all season?

“We’ll probably play more man (coverage). We might load the box a little bit more,” cornerback Chris Harris said. “We’re going to have to cover longer this week for sure. D-line has to do a great job of keeping contain; if we can keep them in the pocket and pressure them from there, it’s going to be hard for them.”

For Denver to make that plan work, it will need to place Tennessee in uncomfortable positions. The Titans rank first and fourth, respectively, in red-zone touchdown percentage and third-down percentage, largely because of their ability to run the ball well.

“They have a ton of formations. They’re a big football team,” Broncos coach Gary Kubiak said. “This team is capable of pounding you. We’ve had some issues with the run, so we know we’re going to get tested.”

Murray and Henry have impressed Kubiak.

“For two big guys, they make a lot of big plays,” he said.

Murray, the AFC’s leading rusher with 1,043 yards, will challenge the Broncos linebackers’ gap discipline with his combination of vision, power and speed. Henry, a 6-foot-2, 247-pound rookie, is averaging 4.5 yards a carry, and he’s a load to tackle. Tennessee is averaging 141.5 yards rushing per game.

Tennessee built one of the NFL’s best offensive lines by shifting its identity.

“They’re a mauler-type offensive line. You have to make them one-dimensional,” outside linebacker DeMarcus Ware said. “They’re hogs. If you let them run the ball, that’s what they love.”

The Titans will try to keep the Broncos in their 3-4 base defense, meaning more of nose tackle Sylvester Williams and inside linebackers and less of cornerback Bradley Roby, in order to limit the Broncos’ knack for making explosive defensive plays. Roby’s pick-six last Sunday was the difference in the Broncos’ victory at Jacksonville.

Slowing down Murray and Henry isn’t enough, however. Mariota, particularly when he runs the zone read, is a weapon on the ground. He’s the NFL’s fourth-leading rushing quarterback, but he may be the most dangerous in terms of his speed and ability to read the defense.

“Running quarterbacks have been killing us all year,” Harris said. “We need to tighten up for sure, especially this week. This guy is the fastest quarterback in the league. We can’t let him get loose at all, because he’s able to take it the distance.”

Running wild