ALAMEDA — Absence may or may not make the heart grow fonder, but Oakland Raiders coach Art Shell is counting on it improving performance and refreshing their spirits.The Raiders wrapped up their bye week practice schedule Thursday, then raced to their cars for three days of R&R — days Shell hopes will refresh his troops as they come off an exasperating 0-2 start.”I want them to get away and relax, get with their families, enjoy themselves,” he said. “While they’re away, I know some of them will be thinking about what they’re supposed to do, how they can get better, how they can help the team get better. I know that’s going to happen because that’s the nature of an athlete.”

When the NFL posted its 2006 schedule, it was believed the Raiders — along with Dallas, Kansas City and San Diego — were the unfortunate teams to receive the first byes of the season. Most teams prefer the bye come later in the year, when teams begin to wear down and could use the rest more.

But in the cases of all but San Diego, it turned out to be a plus.

The Raiders (0-2) have injuries at quarterback (Aaron Brooks), offensive line (Robert Gallery) and in the secondary (Fabian Washington, Nnamdi Asomugha) that need to heal.

Dallas (1-1) will get an extra week to allow receiver Terrell Owens’ broken finger to heal. Kansas City (0-2) will get a week off to extend the recovery time for quarterback Trent Green (concussion).

San Diego, off to a 2-0 start, is the one team that doesn’t need the additional time for wounds to heal. The Chargers are in danger of having a hot streak interrupted.

The Raiders find themselves in the diametrically opposite classification.

“It (the bye) comes at a very good time … for us injury-wise, and it’s good for us to take a hard look at what we’re doing and how we’re doing things,” Shell said.

What the Raiders are doing is leading the NFL in sacks allowed (15) and ranking No. 30 out of 32 teams in rushing. In 120 minutes of play, they have yet to score a touchdown. The situation has gone well beyond criticism.

Accordingly, the Raiders have become pin cushions for jokes such as the one that said a recent Raiders practice was postponed for two hours following discovery of a mysterious white powdery substance on their practice field. Fearing a terrorist plot, a hazardous materials team was brought in upon which it was determined the substance the team couldn’t identify was the goal line.

“I think it (the criticism) is merited,” guard Barry Sims said. “Obviously. We’re last in the league in sacks given up. You can never be proud of something like that. We’re last in a lot of offensive categories. We’re not getting the job done.”

“Criticism is part of this business,” Shell said. “It’s always been in there. And you can’t, as an individual player, allow that to seep into your brain. Most players will look at themselves and will be more critical … than you guys are. They will be more critical of themselves than the coaches are of them.

“It’s not the end of the world. You don’t stop because two games are gone, and you’re not doing the things you want to do.”

After a 4-1 preseason record, the slow start — particularly by the offensive line — was unexpected.

“I was surprised, to be honest,” Shell said. “I expected better. It’s not like they aren’t trying. They’re good kids. They work hard and want to do well. But wanting and doing are not the same thing. Our job is to try to get them better.”

Over their three-day work week, the Raiders worked at their deficiencies, went back to fundamentals, and the coaches — who will stick around for an extra day today — will review game-plan issues. Shell will give his coaches Saturday and Sunday off.

As for Shell, he will “take care of some things I’ve been putting aside. I need to go to the dentist and go see another doctor. I need to do some honey-do’s … and I’ll probably stop in the office and do some work, too.”

The way the season has been going up to now, the dentist’s visit may be the least painful of his tasks.

EXTRA POINTS: Although they contacted former Steelers QB Tommy Maddox this week, the Raiders have not signed a third quarterback, and Shell said in all probability no one will be signed immediately, if at all. … The work load of LT Robert Gallery (calf) was increased Thursday, bolstering the possibility he might play a week from Sunday against Cleveland. … RCB Asomugha (foot) practiced Thursday and could be ready for the Browns. Shell also said LCB Washington (ankle) might get the go-ahead for Cleveland.