ENGLEWOOD, Colo. --When it comes to mobility, Philip Rivers will never be confused with Colin Kaepernick. He's never averaged more than 2.7 yards per carry, and in just the last four weeks, San Francisco's quarterback has two runs longer than any by Rivers in his 11-season career.
But Rivers has one of the best innate feels for the pass rush in the game. The quick timing and precision of the Chargers' offense since their hire of former Broncos offensive coordinator Mike McCoy has brought it out in a way unseen during his years under Norv Turner.
Rivers' sack rate has dropped -- from one every 15.1 passes from 2010-12 to one every 19.8 passes the last two years. His completion percentage has increased, to a career-high 69.5 in 2013, and a still-outstanding 67.4 this year that is fifth-best in the NFL.
"There's no secret, he's most comfortable stepping up in the pocket," said Defensive Coordinator Jack Del Rio. "It will be important for us to get a little push in there and not let him be comfortable stepping up."
When Rivers steps up, he is unafraid to drop the ball into tight spaces, and fearless under the pass rush. That combination makes him not only effective, but frustrating to a defense, which thinks it has him -- then watches as he drops in a perfect pass to a target like tight end Antonio Gates, who needs only a bit of separation to make a grab.
But the same is true for all targets, as Kayvon Webster learned last year, when Rivers completed passes to three different receivers against him -- despite Webster's tight coverage.
"Kayvon had some great coverage and he was able to just fit the ball in," said Chris Harris Jr. "So you can't be discouraged. We're definitely going to make those throws a challenge. He's going to have to make some perfect throws."
Because Rivers still manages to exploit proper coverage, the onus is on the pass rush to not only penetrate, but prevent Rivers from stepping up,
"He does that really well," said DeMarcus Ware, "so we have to make sure when you're rushing with the inside guys, you have to be able to get good pocket presence so he can't step up so the guys that are rushing outside are able to still get that five- to seven-yards range where you can get to the quarterback if you're going around the corner or doing an inside move."
Another option is a quick pass rush that attacks before Rivers can find his hot read, forcing an errant throw. The Cardinals found some success with this in Week 1, containing the San Diego offense long enough to buy time for their offense to awaken and rally in the fourth quarter.
"The pass rush is going to be big," said Broncos linebacker Brandon Marshall. "(Rivers) drops it in, and if we can get him off the spot, if we can get him to run and try to use his legs -- which is not his best asset -- then that will be a win for us on that down."
The Broncos have one advantage other teams do not: an understanding of how to mentally handle facing a quarterback who beats good coverage. You can't get frustrated when you play Peyton Manning, and the same is true against Rivers, because you can do everything right and come out on the losing end of a play.
"Just because you practice versus a guy who does it correct as well, doesn't mean that you can't be beaten," said safety Rahim Moore. "But (that) doesn't mean that you can't make a play.
"At the end of the day, this is the NFL, and Philip Rivers is a great quarterback. I believe he's going to be a first-ballot Hall of Famer. I think he doesn't get enough credit. I think he's very underrated, but he's still rated the way he should be, as a top quarterback in this league. I'm looking forward to it. It's going to be a tough matchup."