ENGLEWOOD, Colo. -- The Denver Broncos are changing gears on defense this week because of a running back who can shift gears in a hurry.
After modifying their defensive schemes for Peyton Manning, the Broncos will adjust again for talented Tennessee tailback Chris Johnson.
Not exactly an easy transition.
Like Manning, though, Johnson is one of the best in the business, the kind of potent player that forces defenses to adapt their approach.
For Manning, the Broncos often employed multiple defensive backs, frequently using safety Brian Dawkins in coverage packages during a 27-13 loss last Sunday.
For Johnson, the Broncos will likely stack the line of scrimmage, possibly inching Dawkins closer to the action Sunday.
"He's a guy where you can't just hit him and think he's going to go down," Broncos cornerback Champ Bailey said. "He breaks a lot of tackles and makes people look stupid all the time."
The speedy Johnson became just the sixth player in NFL history to top 2,000 yards last season.
So far this year, he's gained 301 yards -- fifth-most in the league -- but hasn't had that headline-grabbing game yet, such as his 228-yard performance against Jacksonville in 2009.
And that has the Broncos on edge.
"He might be one of the most explosive, dynamic backs that I've ever seen and played against," Dawkins said. "He's so patient in the hole and once he sees a gap, he has those gears to get it to the house in a hurry."
Although Johnson is renown for his blazing speed, Broncos coach Josh McDaniels is just as mesmerized by his tenacity. Rarely does Johnson go down with just one hit.
"He's made some great runs just with toughness," McDaniels said.
Just don't forget that quickness. Many a defender has, as McDaniels often points out to his team.
"You never have an angle on Chris Johnson," McDaniels said. "There's a lot of film where it looks like you're supposed to and the angle dissolves or disappears quickly and you end up grasping at the air because he just goes right by you.
"You could be 10 yards ahead of him and think you have a shot. Then, at end of the run, he's in the end zone on the film and there's nobody else in the picture."
The Broncos are certainly getting the picture.
"We have to make sure there's a party at the ball," said Dawkins, who returned to practice Thursday after missing a day with an ankle ailment. "Everybody has to be there, make sure your gap is sound, set those edges and for everybody to run to the football."
This has been a challenging week for the Broncos, switching gears from the pass-happy Colts to the run-oriented Titans.
Denver employed five, sometimes six defensive backs against the Colts and took away Manning's top two targets in Reggie Wayne and Dallas Clark.
It didn't matter as Manning simply found Austin Collie and Blair White instead.
However, the Broncos were able to neutralize Indy's ground game, limiting the Colts to 40 yards on 22 carries.
The Titans are a totally different monster, though. Johnson's their workhorse, carrying the ball an NFL-high 75 times this season.
"Every time he touches the ball, it's electric," Broncos defensive coordinator Don "Wink" Martindale said. "It's a challenge anytime he hits the field. He's one of the best backs there is in the league. You have to keep your focus on him at all times."
All the while not forgetting about Vince Young, who's a threat to take off every time he takes a snap.
"He kind of reminds me of Michael Vick a little bit, and we all know how dangerous he's been the last few weeks," said Bailey, who's recovering from a sore heel. "Vince still has that kind of talent."
Stopping Johnson, though, remains the top priority.
"If you lose your focus for one second, then he makes you pay for it with a 60-yard gain," Martindale said. "There's no angles that you can have on him, because he is lightning-fast."
Johnson's success doesn't really surprise McDaniels because when McDaniels was the offensive coordinator in New England, the Patriots took a look at Johnson before the 2008 draft, admiring what they saw.
Johnson, an East Carolina product, ended up going to the Titans with the 24th overall pick.
"I don't know that anybody could've projected what you're seeing from him last year and then even this year," McDaniels said. "Anytime you're mentioning Jim Brown, comparing a player to that type of a player in the past, you know he's doing really special things."
NOTES: RB Knowshon Moreno (hamstring), LB Wesley Woodyard (hamstring) and FB Spencer Larsen (ankle) missed practice for a second straight day. ... Broncos OL Ryan Harris (ankle) practiced Thursday on a limited basis.