The Chicago Bears and Washington Redskins have both looked like teams with legitimate playoff aspirations at times this season. They each have a lot to work on, however, to make those playoff dreams a reality.

The Bears again try to get their sluggish offense on track Sunday when they host a Redskins team that is struggling mightily defensively.

Chicago (4-2) leads the NFC North despite major issues on a makeshift offensive line. The Bears have offered little protection for Jay Cutler, allowing an NFL-worst 27 sacks, and have had trouble opening lanes for Matt Forte to run, ranking 26th in rushing at 92.3 yards per game.

Chicago used its fourth different starting offensive line in Sunday's 23-20 loss to Seattle, with Chris Williams -- who had missed three games with a hamstring problem -- replacing the injured Roberto Garza (knee) at left guard.

It didn't appear to help. The Bears rushed for 61 yards, while Cutler was sacked six times. Cutler, who when he stayed upright went 17 of 39 for 290 yards, was playing for the first time since suffering nine sacks and a concussion in a 17-3 loss to the New York Giants on Oct. 3.

Although the line's poor play has made things difficult, coach Lovie Smith remains confident.

"You mean the four wins that we have with this offensive line? That is what convinces me," he said. "We've won four games with this offensive line. You have to keep in mind, too, with the offensive line we've worked different combinations. I'm excited about this week hopefully having the same combination start the game and play together."

Smith might also be excited to face a Washington defense that has struggled to stop anybody.

The Redskins (3-3), one game behind Philadelphia and New York Giants in the NFC East, are allowing an NFL-worst 432.5 total yards per game. In last Sunday's 27-24 loss to Indianapolis, Washington permitted 469 yards -- including 170 on the ground, the most by the Colts in more than three years.

"It bothers me a lot. I'm not used to being on defenses that rank last in the league. That doesn't sit well to me," linebacker London Fletcher said. "I'm not going to be naive and think that we're going to hold Peyton Manning and that offense to 200 yards. That's not realistic. But should they have 469 yards on us? No. That's not something we're going to accept, either.

"We can't week-in and week-out give teams 400-plus yards, 500 yards. That's just ridiculous."

In the Redskins' defense, they have already faced four of the top five offenses in the league. They appear to have a good chance of cleaning up some of their defensive miscues against a Chicago team that is 26th in total offense at 313.2 yards.

While most of the Bears' problems have stemmed from a shaky offense, the defense has helped keep the team competitive with 14 takeaways -- tied for third in the NFL. The unit should receive an additional boost from five-time Pro Bowl linebacker Lance Briggs, who is expected to return after sitting out last week with an ankle injury.

The Redskins, already without starting running back Clinton Portis (groin), will have Chris Cooley on the field even though the tight end suffered a concussion against the Colts. Cooley has emerged as one of Donovan McNabb's favorite targets, catching 28 passes for 340 yards with two touchdowns.

McNabb, who has thrown one exactly one TD pass in five straight games, has faced the Bears each of the last three seasons with Philadelphia, throwing for 732 yards with four touchdowns and two interceptions.

This will be Washington's first game against Chicago since a 24-16 home win Dec. 6, 2007, when current Bears backup quarterback Todd Collins completed 15 of 20 passes for 224 yards with two touchdowns and no interceptions for the Redskins.