Before starting his first practice as Oakland Raiders interim coach, Tony Sparano dug a hole and placed a football in it and had the entire team bury it with dirt as a symbol of putting the first four games in the past.

Whether that act proves to be anything more than a nice symbol will be the true sign of whether the move to fire Dennis Allen and replace him with Sparano can save what is looking like a lost season in Oakland.

The first test comes Sunday, when the Raiders (0-4) host the San Diego Chargers (4-1) in their first division game of the season.

"You approach it with arms wide open. You got to embrace it. You got to take it in," defensive tackle Antonio Smith said of the change.

"When you don't embrace any change, all you're doing is helping you to stay the same you were, and where we were at wasn't that good. I'm going to embrace it with arms wide open."

The streaking Chargers come into their first division game with a bit of caution unsure of how different the Raiders will look under their new coach.

San Diego has won four straight games to move to the top of the AFC standings, but can't afford any slipup against a lesser team with Denver close behind in the division.

"You don't know exactly what's going to happen, but you can't prepare for what you just don't know," linebacker Dwight Freeney said. "You start playing that game of 'Oh, they could do this, they could do that.'

"You end up playing nothing in the game because they could possibly just do the same thing and you'd be hitting yourself over the head. So, we're going to go out there and just prepare for them as of what they've shown."

Here are some things to watch when the Raiders host the Chargers:

RIVERS RISING: San Diego quarterback Philip Rivers is playing some of the best football of his career, posting a passer rating of at least 120 in each game during the four-game streak. Only Kurt Warner and Johnny Unitas have streaks that long in NFL history, but Rivers knows how quickly fortunes can turn.

"The one thing about it is when you've won a handful in a row that you can't just think that winning is easy," Rivers said. "It's hard to win a game every week and we have that mindset."

CAPTAIN CARR: Sparano pulled quarterback Derek Carr aside soon after taking over as coach and told him the team had no time for Carr to be a rookie anymore with a leadership void on the losing team. Carr has shown progress in his first four starts, but has not done enough yet for a win.

"He'll continue to grow," Sparano said. "He's had some bumps along the way here, bumps in the road, and he learns from them. But, we're happy with what he's done."

BUFFALO BUDDIES: For a school that is far from a football powerhouse, Buffalo has turned out two intriguing rookies this season. Oakland linebacker Khalil Mack is living up to expectations after being fifth overall but his former college roommate, Branden Oliver, has been a revelation in San Diego. The undrafted rookie ran for 114 yards and a TD last week against the Jets in a performance that was a surprise to almost everyone other than Mack.

"I let everybody know during the draft process that he was one of the best running backs that I ever played against, even though it was practice," Mack said.

COACHING COMRADES: Allen and Chargers coach Mike McCoy are longtime friends who worked on the same staff in Denver and take family vacations together. McCoy said he has talked to Allen since his firing and is confident his friend will get another chance as an NFL coach soon.

"That's all part of the business," he said. "We're doing our thing here, and it's all part of the business. We all understand that when we get into it, it's part of the process."

GROUNDED: Sparano promised a stronger commitment to the run game as soon as he took over. The Raiders were the most pass-heavy team under Allen, throwing the ball on more than two-thirds of their offensive plays. That was in part because of early deficits and also because Darren McFadden and Maurice Jones-Drew were ineffective. Oakland is averaging 3.4 yards per carry, a number that needs to improve if Sparano can rely on the run as much as he wants.

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AP Sports Writer Bernie Wilson in San Diego contributed to this report.

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