Cardinals quarterback Carson Palmer and running back Chris Johnson both got off to a good start to the 2015 season.

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TEMPE, Ariz. -- The Arizona Cardinals are putting up impressive statistics.

With big-play options galore, they lead the NFL in scoring and touchdowns.

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Their offense is ranked No. 3 in the league, their defense No. 4.

Yet just how good coach Bruce Arians' team is remains to be seen. No team the Cardinals have beaten had a winning record heading into Arizona's bye week. And the schedule gets a whole lot tougher now.

"I don't think the identity of our ballclub has been identified yet," Larry Fitzgerald said. "Coach says it all the time: This is our football team. We're only going to be as good as we decide to be."

Arizona has racked up 263 points. The Cardinals' 32 touchdowns, through eight games, match their total for all of last season. They have twice as many TDs as their opponents have scored against them. Yet the team has had a habit of slipping into what Arians has called "lulls."

They've overcome such lapses enough to compile a 6-2 record, good enough to lead St. Louis by 1½ games and Seattle by two games in the NFC West.

Of the teams the Cardinals have beaten, New Orleans is the best of the bunch at 4-4. The other wins have come against Chicago (2-5), San Francisco (2-6), Detroit (1-7), Baltimore (2-6) and Cleveland (2-6).

"We can be better," quarterback Carson Palmer said. "We can fire on all cylinders more often, because the lulls, you can get away with them in some of the games we've gotten away with them. But coming up, we can't afford those lulls."

First up after the bye is a game at Seattle. The rest of the schedule includes Seattle (again), Cincinnati, Minnesota, Green Bay and a road game against St. Louis, which beat the Cardinals in Arizona.

"We've got some really, really, really tough teams," said Fitzgerald, among a trio of 30-somethings who have had a fountain-of-youth type first half of the season in the desert.

Palmer, at 35 and coming off surgery to repair a torn ACL, is playing the best of his career. His 20 touchdown passes match Tom Brady for tops in the NFL.

The 34-20 win at Cleveland last Sunday marked the second time this season Palmer has thrown for four scores in a game. His quarterback rating of 110.2 ranks third in the league, behind Brady (115.8) and Aaron Rodgers (110.9).

Arians was asked on Monday if Palmer should be considered alongside Brady and others for league MVP.

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"I don't see why not," the coach said. "He's playing right there with them, if not better."

Fitzgerald, 32 with a new two-year contract, has 55 catches for 706 yards, on pace to threaten his career bests of 103 receptions (set in 2004, his second NFL season) and 1,411 yards (set in 2011). His seven touchdown catches are tied with Odell Beckham Jr. and Rob Gronkowski for most in the NFL. Palmer also has called Fitzgerald the best blocking wide receiver in the league.

Which leads to 30-year-old running back Chris Johnson. With a bullet in his shoulder from an offseason shooting that he thinks scared teams away from him, Johnson signed with Arizona late in the preseason and has shown he still has the talent that made him one of the league's best in his years with Tennessee.

Johnson ranks second in the NFL (behind Atlanta's Devonta Freeman) with 676 yards rushing. He's the catalyst of a strong running game that's freed up Palmer for big play-action plays. The consistently effective running game, Palmer said, is the biggest difference between this year's Cardinals and those of the past two seasons.

On defense, Arizona leads the NFL with 13 interceptions - by seven different players. Safety Rashad Johnson has four.

Cornerback Patrick Peterson is shutting down the opponents' best receivers and safety Tyrann Mathieu is seemingly everywhere on the field.

Yet the players acknowledge they haven't put it all together yet.

Fitzgerald points to last Sunday's game against Cleveland as "a perfect example." Arizona trailed 20-10 at the half only to outscore the Browns 24-0 after that.

"That's a 5-11 football team there in the first half," he said. "Then we come out in the second half and show what we're capable of. We were a completely different football team."

But Arians isn't complaining, too much anyway.

"Could we be better?" he said. "Hell yeah, but I like where we're at right now."