ALAMEDA — Four games into the season, a Raiders defense recalibrated with takeaways in mind has yet to record its first interception.

“I wouldn’t have believed it,” safety-turned-cornerback Michael Huff said as the Raiders returned to work after four days off.

The modernized Raiders defensive scheme was one of the main storylines of training camp.

Mixing coverages would assure cornerbacks the chance to play some zone and break on the ball. Safeties would play “downhill” with a better chance to jump routes. More frequent blitzing and a stout front four would assure quarterbacks would throw before they were ready.

Instead, the Raiders have given ground steadily to an endless procession of short passes, most recently by Ben Roethlisberger and Peyton Manning, and Sunday will see much of the same on the road against the unbeaten (5-0) Atlanta Falcons and quarterback Matt Ryan.

The Raiders and the Detroit Lions are the only two teams in the NFL that have no interceptions. The Raiders and Jacksonville Jaguars have the fewest sacks in the NFL, with three each.

“For us to not have any picks and only a few sacks just boggles the mind,” Huff said.

Factors that have contributed to the Raiders struggles have included injuries and experienced quarterbacks who have been accurate and throwing quickly to avoid the rush.

Cornerback Ron Bartell (broken scapula) was lost in the opener for at least six weeks and Shawntae Spencer, the other starter, went down in Week 2 with a foot sprain and is likely out at least another week or two.

Huff was pressed into emergency service at cornerback with Pat Lee as the other starter, and Matt Giordano became the free safety. Roethlisberger and Manning were a combined 69 of 88, with the closest thing to an interception coming when Lee dropped a Manning pass right in his stomach.

Coach Dennis Allen believes it is up to his defense to force the issue, regardless of how offenses are attacking it.

“We call them takeaways, which means that we control them,” Allen said. “It’s not like the offense gives us the ball. We go out and take it away from them. There are things we can do.

“We’ve got to have 11 people flying around to the football like their hair’s on fire. That’s the way you play defensive football. It’s been that way since the beginning of time, and it won’t change.”

Tyvon Branch is at his usual place among the top of the Raiders tackle chart with 58 but has just two interceptions in 52 games as a starter despite improving his coverage skills the past two years.

“We’ve definitely got to get some interceptions,” Branch said. “Once we start getting interceptions, that will help our pass rush. Everything works hand in hand. We’ve got to start covering better, and the pass rush will start getting some sacks.”

Teams have been attacking the defense so consistently with short passes Huff believes the Raiders may reach back into the Al Davis defensive playbook.

“That’s when you’ve got to play (man-to-man), like the old days,” Huff said. “Get tighter to the receivers, because obviously there’s holes in every zone, so games like that you’ve got to play more man. So we’ll see.”

Spencer, right tackle Khalif Barnes (groin) and tight end Richard Gordon (hamstring) were still out after four days off. Spencer’s injured foot remains in a boot.

On the one-year anniversary of the Davis’ death, defensive tackle Richard Seymour recalled the day he was traded from the Patriots to the Raiders. “He asked me, ‘Where are you right now,’ ” Seymour said. “I told him, ‘New England.’ And he said, ‘I’m in sunny California.’ One thing I knew was how much he loved his players, and his players always wanted to win for him, because they knew how much he cared about them.”