The San Diego Chargers and Oakland Raiders are both struggling and facing major questions about their quarterbacks.

They won't have much time to solve their issues.

The AFC West rivals meet Thursday night in San Diego, with the winner guaranteed at least a share of the lead through the weekend in the NFL's weakest division.

San Diego and Oakland are both 4-4 to tie Kansas City for the West lead, with Denver one game back in the league's only division where no team currently owns a winning record. The Chargers have lost three straight and the Raiders have dropped two in a row.

"There's three teams deadlocked in the division and Denver's spotting us all a game," Chargers quarterback Philip Rivers said. "They're right there in the thick of it. All four teams are alive. We've got eight to go. We'll see what happens."

Rivers has contributed to the Chargers' woes. He's thrown an NFL-high 14 interceptions -- one more than he had all of last season and one shy of his career high. Although Rivers' 2,469 passing yards are the league's fifth-most, his mistakes have been crucial.

"That's something I need to keep working on and do a better job of," he said.

It seems there is plenty for new Oakland quarterback Carson Palmer to work on as well. Palmer has six interceptions in two losses since joining the Raiders to replace an injured Jason Campbell, and he's dropped nine straight road starts to AFC foes entering this contest.

"I'm really looking forward to having a chance to go out and put better play on film and just go out and be successful," said Palmer, who grew up in nearby Orange County and will play his second career game at Qualcomm Stadium. "It was overwhelming at first and it's slowly died down and now I kind of feel like I'm in the middle of the season like I should be."

There could be plenty of pressure on Palmer and the Raiders' passing game since top rusher Darren McFadden will miss a second straight game with a sprained right foot. McFadden ranks sixth in the league with a 5.4 per-carry average.

"Obviously you'd always like to have your best players, but we're not going to make any excuses," Raiders coach Hue Jackson said. "We've lost because we haven't played very good football."

The Raiders ended a 13-game losing streak against the Chargers by sweeping two meetings last season, one of them without an injured McFadden.

"We haven't beat these guys since '09," Rivers said. "We lost both of them last year and obviously that had a big impact on us not making the postseason. So it's a huge game for both teams."

The Chargers also may be short a running back after top rusher Ryan Mathews missed Sunday's 45-38 home loss to Green Bay with a groin injury. Mike Tolbert returned from a hamstring injury to get the start, and rushed for a season-high 83 yards and a score along with four receptions for 59 yards.

San Diego has not lost four straight since opening 0-5 in 2003.

The Chargers, however, usually make their move now. They are 26-6 in the second halves of the last four seasons -- tied with New England for the NFL's best mark.

Both teams' defenses have shown a tendency to falter late in games. Oakland has allowed the league's most fourth-quarter points with 76 and San Diego is tied with the Patriots for the second-highest total with 73.

"If you don't play well, you're going to lose games," said Chargers safety Eric Weddle, tied for the league lead with five interceptions. "We just want to go out and play a complete game and win it and move on and get on to the next week."

Oakland continues to play with a startling lack of discipline, leading the league with 84 penalties for 730 yards. The Raiders got flagged for 15 penalties worth 130 yards during last week's loss.

"We've got some work to do, we've got some growing to do," Jackson said. "Our guys are excited because they know we are 4-4 and still in the thick of this thing. What we need to do is get a win."

The Chargers have been whistled for 33 infractions for 264 yards during their losing streak. They did not commit a penalty in their last victory, 29-24 at Denver on Oct. 9.