ENGLEWOOD, Colo. (AP) When Darian Stewart followed Gary Kubiak from Baltimore to Denver in the offseason, he declared himself the ''final piece of the puzzle'' in the Broncos' star-studded secondary.

What he lacked in the Pro Bowl trips that Aqib Talib, Chris Harris Jr. and T.J. Ward have all made, Stewart more than made up for in bravado.

It turns out that wasn't just bluster, either.

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The newest member of the ''No Fly Zone'' has helped Denver build the league's top defense. The Broncos (10-2), who face Oakland (5-7) on Sunday, are the only team in the NFL that hasn't allowed a 300-yard passer all season.

Kubiak and defensive coordinator Wade Phillips call the sixth-year safety the quarterback of the secondary.

Save for his big pronouncement when he signed a two-year, $4.25 million contract in March, Stewart is quiet and reserved off the field. But he embraces the role of being a big talker and a big hitter on the field.

''You're just running the show. You're the one who talks the most on the field, you have to be verbal as a free safety, being able to line each other up and just knowing the defenses and making sure your corners get the calls so they can play the right technique,'' Stewart said. ''That's pretty much the whole thing about being a free safety is just making sure everyone's lined up.''

That could prove especially critical Sunday against the Raiders with Ward (ankle), David Bruton Jr. (knee) and Omar Bolden (hamstring) all hurting. Reinforcement Josh Bush is playing in his second game of the season and newly signed safety Shiloh Keo is making his Denver debut.

''Most definitely. I think it's critical,'' Stewart said. ''Even with the original players out there, because on the back end man, one play, one mess-up, that can be a touchdown. So, communication is key.''

Stewart has collected 49 tackles, eight pass breakups, a forced fumble, two fumble recoveries and an interception this season, although his biggest hit was a pass breakup that knocked Patriots tight end Rob Gronkowski out with a knee injury two weeks ago.

Stewart replaced Rahim Moore, who left for a three-year, $12 million deal with Houston, in the lineup. The versatile Stewart is a better tackler than Moore, best known for getting beat on Jacoby Jones' 70-yard touchdown in the playoffs three years ago.

Stewart played in St. Louis from 2010-13 after going undrafted out of South Carolina, then had a solid season in Baltimore last year, securing the Ravens' wild-card win over Pittsburgh with a late interception in the end zone.

He's having his best season yet in Phillips' defense that simplifies matters and allows for fast, instinctive play.

''He fits great,'' Talib said. ''D-Stew fits great. Having two safeties that will come down and pop you like that puts a lot of fear in (receivers') hearts. We kind of lacked that last year from the free safety. Stew definitely brought that to the table and you can see how much it's helped us.''

The Broncos have enough coverage skills to free Stewart to do what he does best: read the play and go hit the guy with the ball.

''Man, he's been a great pickup,'' Harris said. ''He has great intelligence back there. He kind of sees where the quarterback's going to attack. We're telling Stew to just trust me and Talib to shut down receivers and go help on those tight ends. And when those tight ends are catching the ball, he's coming down and just laying the hammer and that's what we need.''

Notes: TE Vernon Davis made enough progress in concussion protocol to resume practicing Thursday. ... OLB Shane Ray was sent home sick with a sore throat. ... QB Peyton Manning threw on his own for a second day. Manning will miss his fourth straight game Sunday. ... Kubiak said he wouldn't hesitate to start Juwan Thompson if he has to with Ronnie Hillman (foot) and C.J. Anderson (ankle) ailing. ... OLB DeMarcus Ware (back) is set to return from a four-week absence and NT Sylvester Williams (ankle) is expected to return Sunday after missing last week's game. ... Phillips on Von Miller's sack dances: ''I don't really know what he's doing, but I'm glad he's doing it.'' And, no, Phillips has no two-step tips for his fellow Texan: ''I can only do the YMCA and that's about it,'' Phillips said.

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Follow AP Pro Football Writer Arnie Melendrez Stapleton on Twitter: http://twitter.com/arniestapleton