NAPA (AP) — Tommy Kelly needed only one preseason game to become convinced Oakland's defense is already vastly improved from a year ago.
The veteran defensive tackle has fully embraced the changes made by first-year coach Dennis Allen and defensive coordinator Jason Tarver and said he expects the Raiders (tied for No. 23 in the AP Pro32) to have one of the top five defenses in the NFL in 2012.
"Most definitely," Kelly said following practice Thursday. "(If) we cut down on the mental errors and the penalties, man, people are going to have a hard time dealing with us."
That might be asking a bit much from a team that ranked 29th in overall defense and surrendered the second-most touchdowns in the league last season.
Then again, Kelly has been defying odds since he entered the NFL as an undrafted rookie in 2004.
A Pro Bowl alternate each of the past two seasons, Kelly has developed into a player who Allen believes can be one of the game's premier defensive tackles. Allen is counting on the 6-foot-6, 300-pounder to help anchor Oakland's front four.
The Raiders' first-team defense got off to an encouraging start in the 3-0 loss to Dallas on Monday, allowing only three yards rushing in two series. Kelly also sacked quarterback Tony Romo for a 12-yard loss to force the Cowboys into a third-and-24 before they punted.
A small sampling, to be sure, but Kelly likes what he's seen so far.
"It's the first time in nine years we ever looked that good tackling in the first game of the preseason," Kelly said. "So whatever they're doing must be working. We look a lot better."
The Raiders play in Arizona on Friday, their second preseason game in five days, but will be without starting free safety Michael Huff, who will be attending the birth of his first child.
Oakland will also be minus outside linebacker Aaron Curry, who has been in Los Angeles for nearly a week undergoing treatment on his knees. Curry has not practiced at all this camp and remains on the active-physically unable to perform list.
Allen hasn't ruled out Curry returning in time to play in the Raiders season opener Sept. 10 but acknowledged time is starting to run out.
All of Oakland's starters will take increased reps against Arizona, a normal progression for NFL teams in the preseason.
Kelly, for one, is looking forward to it.
After missing the offseason workouts last season because of the lockout, the 31-year-old spent the year battling a variety of nagging injuries yet still had a career-high 7 1/2 sacks and recorded his first NFL interception.
"It was always hurry-up mode," he said. "Going the whole offseason without any contact I had more problems with my body last year than I ever had in my career. But I made it through the year, so that's all that matters."
Keeping Kelly healthy is critical for the Raiders this season.
He hasn't missed a game since suffering a season-ending knee injury midway through the 2007 season and is the longest-tenured player along Oakland's defensive line.
The numbers suggest Kelly is only getting better. He has 14 1/2 sacks over the past two seasons and has averaged nearly 53 tackles a year since his injury-shortened season in '07.
In the Raiders new defensive system, Kelly will be used at a variety of positions. He will line up primarily at tackle in Oakland's 4-3 scheme but will also move up and down the line.
Allen, a former Denver Broncos defensive coordinator, believes Kelly can be even better than he has been the past two years.
"He can be one of the premier inside players in the league," Allen said. "He's working on trying to develop a little bit more from a fundamental standpoint, and if he does those little things, he'll begin to get recognized as one of the top interior players like he's played."
Notes: Allen said the quarterback rotation will remain the same for Friday's game in Arizona. ... The Raiders signed LB Korey Bosworth, nephew of former NFL player Brian Bosworth.