ALAMEDA, Calif. (AP) -- The Oakland Raiders will have to deal with one of their toughest defensive tests without one of the leaders in their secondary.
Starting strong safety Tyvon Branch will likely miss significant time with a right ankle injury starting with next Monday night's game against Peyton Manning and the high-powered Denver Broncos.
Branch is one of two returning starters on a much-improved defense for Oakland (1-1) that leads the league with nine sacks and has allowed just three scores on its last 17 drives. Branch got hurt rushing the passer in the first quarter of Sunday's win over Jacksonville.
Coach Dennis Allen would not confirm an ESPN report Monday that Branch broke his leg but said Oakland's highest-paid player in 2013 will be out for ''some time.''
''Man that hurts,'' backup safety Usama Young said Monday. ''Hurts the team. Having a guy like that in the locker room, on the field, in meeting rooms. It's a devastation. As a group you have to put your best foot forward to go ahead and get the next guy up.''
Young and Brandian Ross filled in admirably for Branch on Sunday and both will likely see time alongside Charles Woodson in Oakland's secondary. Ross has played mostly strong safety and Young has backed up Woodson at free safety, but the Raiders could start either one because the positions are similar enough and Woodson has experience at both.
''If Ty's out for a while then we've got guys that we feel can step up and make plays, whether it's strong safety, free safety,'' Allen said. ''To me I look at those as interchangeable positions and they really need to be to be able to have the flexibility to do different things defensively. I think I've got confidence in all three of those guys that are back there.''
Branch has been one of the few constants on a Raiders defense that has undergone major overhauls the past two offseasons. He started 64 of the past 66 games and has played virtually every snap when healthy.
''He's been in the system now for a while and he truly understands the game,'' Woodson said. ''There's not much out there that's going to surprise him as a player. So you're going to miss a guy out there that has a great understanding of what to do and when to do it.''
His absence will be particularly felt this week against Manning and the Broncos. Denver has scored 90 points the first two weeks with Manning throwing nine touchdown passes and no interceptions.
A dangerous offense has gotten even tougher to defend this season with the addition of Wes Welker to a talented receiving corps that already featured Eric Decker and Demaryius Thomas. Welker has 12 catches for 106 yards and three touchdowns in his first two games in Denver, giving Manning yet another option.
''He's the best of the best, you know, and he's seen everything and he probably watches film probably more than anybody else and he's going to know what to look for when he walks up to the line,'' Woodson said. ''The thing with him is you try your best to give him different looks and not let him know when you're in. If he knows what you're in, you see what he's done the first couple of weeks.''
Since allowing touchdowns on the opening two drives of the season to Indianapolis, the Raiders defense has played very well, giving up just two touchdowns and one field goal since then.
Oakland has been more aggressive than a year ago and it has paid off in the sacks, including five from the defensive backs. But the Raiders have been unable to generate any turnovers.
''We have to get the ball,'' Woodson said. ''Not to have any fumbles, not to have any interceptions has been tough. I'm used to having a couple myself at this point. That's what a great defense does. You stop people from moving the ball, you get off the field on third down and you get turnovers. We haven't gotten any over the first couple weeks, and that's something we've got to start doing. That's especially true against a guy like Peyton Manning.''
NOTE: G Lucas Nix is having an MRI on his injured ankle that forced him out of the game in the third quarter. ... Allen said he believes K Sebastian Janikowski's two missed FGs have to do with a lack of comfort with new holder Marquette King rather than bad holds. Shane Lechler had held for almost all of Janikowski's first 13 seasons.
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