As NFL.com's Chris Wesseling reminded readers, a decade ago, Carson Palmer posted a passer rating of 100 or better in nine consecutive games, a stretch that had him on par with Peyton Manning and Tom Brady as the best quarterbacks in the game.

He has since undergone two ACL surgeries, overcome a multi-year elbow injury and suffered nerve damage in his throwing shoulder. Palmer's game had reached the point that he was widely regarded as a washed-up journeyman when he first arrived in Arizona.

But the veteran signal caller has turned things around. He's currently playing the best football of his career just as he's hitting his comfort zone in Bruce Arians' system.

So what qualifies as the "best" for the only player in history with 4,000-yard passing seasons for three different teams?

As Wesseling pointed out, Palmer is first in Profootballfocus.com’s rankings, third in Gregg Rosenthal's NFL.com QB Index, third in ESPN's QBR, third in FootballOutsiders.com's efficiency ratings and fourth in passer rating (114.0). The Cardinals' 190 points are the seventh-most in NFL history through five games.

Over his last 20 games, Palmer has completed 438 of 678 passes (64.6 percent) for 5,475 yards (8.1 YPA), a 40:15 TD-to-INT ratio and a cool 100.0 passer rating. His 17-3 record is the best in the league during that span.

If the numbers aren't enough for you, just as his coach. Arians believes Palmer is playing as well as any quarterback ever has under his watch.

Arians has worked with Manning, Ben Roethlisberger and Andrew Luck.

"He is so healthy now, and he spent so much time building not only the knee but his entire body," Arians recently told Dan Pompei of Bleacher Report. "His arm is live. His legs are so strong with all the rehab he did. And he has a great understanding of what we're trying to get done."

The loftiest praise has come from Larry Fitzgerald, who is experiencing a career renaissance on the other end of Palmer's pinpoint passes.

"He's big, he's strong, he's accurate and he can make all the throws -- and he's playing absolutely great," receiver Larry Fitzgerald said after the team's Week 3 win over the 49ers. "Now he's with a coach who really believes in him, and Carson's completely in command."

Fitzgerald added that Palmer is "best in the business" right now.

"The way he's playing," Fitzgerald added, "I'd put him right up there with Aaron Rodgers and anyone else."

Mobility might be the lone weakness. But Palmer's pocket presence makes has helped to make up for that. It's one of the reasons the Cardinals offensive line has given up just seven sacks in the first five games.

We'll see if it continues against a Steelers pass rush that's tied for fourth in the league with 16 sacks.