TEMPE, Ariz. -- There are two sides to Carson Palmer's time with the Arizona Cardinals: what he did and what could've been.

If Sunday ends up being his final game as a member of the Cardinals -- or as a professional football player, for that matter -- his five seasons in Arizona will be defined by who he was off the field, what he accomplished on it and what was left behind.

"It's been fantastic," coach Bruce Arians said of his time with Palmer. "Some of the best of his career, some of the best of my career -- his numbers and the wins, his leadership. It's just a shame he had the knee and now the arm, or I think he'd have done wondrous things in his time here."

When Palmer wasn't throwing for 4,000 yards -- which he did in three of his five seasons with the Cards -- injuries cut his seasons short. There was the AC joint in his throwing shoulder and the torn ACL in 2014, and the broken arm this season.

Palmer went 38-21-1 in Arizona, which included leading the Cardinals to a 13-3 record in 2015 and a spot in the NFC Championship Game in an MVP-caliber season. It was the deepest Palmer had gone in the playoffs and the closest he has come to a Super Bowl. But just as injuries derailed a 9-1 start the season before, a finger injury affected Palmer throughout that postseason.

The Cardinals' offense hasn't been the same since that deep 2015 run, yet Palmer continued to thrive. He threw for 4,233 yards in 2016 despite Arizona going 7-8-1, after the team implemented a system of rest days to preserve Palmer's arm.

And he was on pace to break 4,000 yards again before suffering the season-ending arm injury in the Week 7 loss in London, a misfortune offensive coordinator Harold Goodwin lamented.

"Who's to know what we could be right now if we had him," Goodwin said. "But, the leadership, the professionalism that he's brought to this team, brought to the organization as a quarterback, I can't be more proud of the guy than the way he's done it. Even though he's been hurt, he's been around every day."

If this is it for Palmer, he has put up Hall of Fame-type numbers. He has thrown for 46,247 yards and 294 touchdowns with a career completion percentage of 62.5. He's 12th all time in passing yards, and every former player with more other than Peyton Manning -- who's expected to be a first-ballot Hall of Famer -- are already in the Hall. And the five active quarterbacks ahead of him -- No. 3 Drew Brees, No. 4 Tom Brady, No. 6 Eli Manning, No. 8 Ben Roethlisberger and No. 9 Philip Rivers -- all might end up Canton, Ohio, at some point.

"He's been a great pro," said Seattle Seahawks coach Pete Carroll, who coached Palmer at USC. "He had an extraordinary college career that he leapt from to get to the NFL. He's been on different teams, and he's always been a fantastic competitor and a great player.

"I've always thought he's about as perfect as a quarterback could be in terms of his size and strength and ability and knack and competitiveness."

When Arians needed a quarterback, he went looking for Palmer.

Arians traded for Palmer in April 2013, just months after he was hired as Cardinals head coach. Arians, a renowned quarterback guru, needed a quarterback. Palmer fit the bill. He's 6-foot-5, 235 pounds, has one of the best arms in football and could make all the throws. He was built, in essence, from the Arians mold, similar to Arians protégés Peyton Manning, Roethlisberger and Andrew Luck.

For Arians, coaching Palmer was different.

When he started coaching Manning, Roethlisberger and Luck, they were either rookies or still early in their careers. Palmer was 33 and married with three children. He's now 38 and has added a fourth child.

"It was totally different," Arians said. "You've got a guy with three kids and older, set in ways a little bit, that you have to change how they read things, how they see things, how they communicate.

"But, it's always fun. Quarterbacks, they just have a great camaraderie in that room on how to learn. Every guy learns different. A young guy, you can brainwash him. A veteran guy, you say, 'You've got to forget some of that. We don't do it that way. That's going to get you in trouble,' and they'll ask you, 'Why?' And you've got to have the reasons why."

When Drew Stanton, Palmer's backup for the past five seasons, was asked what he has taken away from working with Palmer, Stanton said it would take a while to go through everything.

Five years is an "eternity," Stanton said, for a quarterbacks room to stay the same. But more than anything about how Palmer approached the game, his mentality or his preparation, Stanton learned about fatherhood.

"I've got a lot of respect for him, probably as much as anybody that I've ever played with, and genuinely look up to him on and off the football field," Stanton said. "He taught me a lot about being a father and what the balance is like, being able to put your family first, but when you step in here in these walls, everything is football-oriented.

"So finding all of those things, I'm so thankful for the time we've had together and being able to learn from him and take a lot away from him."

Those who have been around Palmer the longest hope he doesn't hang it up, and if he doesn't, there's a chance the decision to part ways with the Cardinals could be made for him. His cap number next season is $20.625 million, and he's scheduled to earn $14 million in 2018, including a $1.5 million roster bonus if he's with the Cardinals on April 1. Those costs could move Arizona to part ways with one of the best quarterbacks in franchise history.

Palmer ranks fourth among Cardinals QBs in passing yards, second in completion percentage and fourth in touchdowns.

"I still think he's got a lot of great football left in him," wide receiver Larry Fitzgerald said. "What he's going to decide to do, I don't know. But whatever he does decide to do, we're going to all respect that and love him regardless."