ESPN analyst Joe Theismann answers five key questions after NFL Week 4:

Which AFC West team has impressed you most so far: Denver, Oakland or San Diego?
The Oakland Raiders are an extremely complete team -- and they're probably the best team in the NFL right now.

	Woodson

The Raiders are getting strong play from QB Rich Gannon, from their special teams and from a still-improving defense. The addition of S Rod Woodson has elevated the Raiders' defense tremendously. He always seems to be around the ball.

The San Diego Chargers are still a young team, especially at quarterback. QB Drew Brees has played well, but if the Chargers have to throw a lot, the jury is still out. And as good as RB LaDainian Tomlinson is, he's only in his second year (like Brees).

QB Brian Griese has stepped up for the Denver Broncos and the defense is playing better. But Rod Smith drives the Broncos' offense. He's the key guy for Griese and for the success of the Denver's attack.

Is the NFC a tossup or have the Eagles established themselves as the team to beat?
I believe the Philadelphia Eagles have established themselves as the team to beat in the NFC. Defensively, they can pressure opponents, they can run the ball and they've got Donovan McNabb.

Who's the best quarterback in the NFL right now? Is it Drew Bledsoe? Rich Gannon? Tom Brady? Or McNabb? In my opinion, McNabb is the most dangerous QB in the league -- maybe not the best, but he's the biggest double threat with his legs and his arm.

The Eagles' defense is impressive because of the pressure it generates on opposing QBs. The Eagles have terrific cover corners, so they can put eight defenders on the line of scrimmage and not get hurt by the big play. They have versatility and speed. When a D has quality cover corners, it's in good position to make plays.

What can the Lions expect from Harrington the rest of this season?
What you're seeing from QB Joey Harrington is what the Detroit Lions expect from him. He can make plays with his legs by scrambling. He can throw downfield, with WR Bill Schroeder as a key deep threat. And he can complete the short, possession passes.

It will just take time for Harrington to grow into the position. He's athletic, so he can make up for a mistake he's made with a read, avoid the sack and still get the ball downfield.

Sunday's 26-21 win over the previously unbeaten New Orleans Saints -- Detroit's first of the season -- isn't necessarily a fluke. The Lions have a chance to win some more games this season. But I base that not so much on Harrington's performance Sunday, but on his debut last week against the Green Bay Packers. In that 37-31 loss, the Lions were explosive on offense.

Coaches and fans love quarterbacks who can ignite explosive offenses.

How do the Rams, Jets and Vikings approach the rest of the season?

	Warner

For the St. Louis Rams, Kurt Warner's injury will keep him out for a while. But they still have Marshall Faulk, Torry Holt and Isaac Bruce. I can't believe the Rams have gone from being so outstanding the past three years to being downright dreadful. Part of the problem has been the ineffectiveness of Warner, the reigning NFL MVP (eight picks and just one TD pass).

It will be interesting to see if the Rams do better with backup QB Jamie Martin -- which would be a role reversal for Warner.

Remember, the well-documented former grocery-store bagger and Arena Football quarterback was given the Rams' job when starter Trent Green went down with an injury in the 1999 preseason. Improbably, Warner led the Rams to a Super Bowl championship that season. The Rams' collapse this season has been just as improbable.

The New York Jets are driven by Curtis Martin, and until they can get him going, their offense will struggle. With QB Vinny Testaverde injured in Sunday's game -- though for how long, we're not sure -- it appears that Chad Pennington will get a chance. If the Jets do well with Pennington at the helm, this has the potential to develop into a Tom Brady-Drew Bledsoe situation.

The Minnesota Vikings are young defensively, which will be their biggest problem as the season progresses. Offensively, they should be able to find their rhythm, but I'm not sure the defense can stop opponents effectively. That's their biggest challenge.

Which defense has more problems to solve heading into next week's AFC East battle between Miami and New England?
The Miami Dolphins probably have the bigger problem because they don't play as many varied defenses as the New England Patriots.

The Patriots got trapped a few times Sunday with too many people in the wrong place around the line of scrimmage, while the Dolphins didn't get the plays they normally get from their secondary. To succeed against Miami, you need to get to MLB Zach Thomas. If you can do that, you can make things happen against Miami's D.

I was really surprised the way the Chargers ran on the Patriots on Sunday. But give lots of credit to the Chargers' offensive line and to RB LaDainian Tomlinson (216 yards). Also give credit to coach Marty Schottenheimer. Some people accuse him of being too predictable with the run, but you win in the NFL by running the ball and playing great defense. Schottenheimer knows how to do both.

A game analyst for ESPN's Sunday Night Football, former NFL QB Joe Theismann won a Super Bowl and a league MVP award. He reviews the NFL each week for ESPN.com in Cup o' Joe.