Quarterback Colin Kaepernick (7) tries to escape linebacker Kevin Minter during last year's Cardinals-49ers game in Arizona.

By the time Patrick Peterson first faced Colin Kaepernick in a game, the Cardinals were finishing a rough 2012 and Ken Whisenhunt was coaching in what turned out to be his final game for Arizona.

Kaepernick threw for 276 yards and two touchdowns in an easy win.

He had evolved into a dangerous multi-faceted quarterback for one of the league's most powerful teams. The 49ers made the Super Bowl in 2012 and the NFC Championship game the next year, and Kaepernick seemed primed to be the driving force the Cards would have to reckon with for years. In his first five starts against the Cards (going 4-1), Kaepernick had a

106.2 passer rating.

Much has changed.

The last time Kaepernick played against the Cardinals, he threw four interceptions in a 40-point loss, last season. The Kaepernick – and the 49ers – the Cards will see this Sunday bears little resemblance from that team battling for the NFC West at the outset of Bruce Arians' tenure with the Cardinals.

"It was shocking for me," cornerback Patrick Peterson said. "It really was. For him to come off those years, it was remarkable. To take control of that football team the way he did … but a lot can factor into why he's not playing as well as he used to. Different coordinators, not having the stable running game they had when (Jim) Harbaugh was there, not having a defense.

"But to see him have such a huge dropoff, it is definitely surprising."

For a while, it looked like the Cardinals would have twin tough quarterback matchups within the division. Russell Wilson and Kaepernick were primed to cause problems. Wilson and the Seahawks have become just that. Kaepernick, battling multiple injuries and now a second head coach since Harbaugh left, may not play for the 49ers beyond 2016.

Nearly traded in the offseason, Kaepernick started the season behind Blaine Gabbert – who was the starter against the Cardinals the past two matchups between the teams – in part because he was still trying to return from serious injuries.

But even before he was hurt, he wasn't playing like the NFC title game Kap. Last September at University of Phoenix Stadium, he not only threw the four picks, but two were returned for touchdowns. The Cardinals won, 47-7.

"That was probably the worst game of my career that I can think of," Kaepernick said. "(Sunday) is an opportunity to go down there and redeem myself."

First-year 49ers coach Chip Kelly said he's still early in his evaluation of Kaepernick, who would seem to be the perfect fit for Kelly's read-option offense. As the Niners have stumbled to a 1-7 start, it's hard to know if Kaepernick will last long-term.

Cardinals defensive tackle Calais Campbell said he always knows the young players in the division that could be an issue. Wilson. Rams running back Todd Gurley. Kaepernick was one of those players, and even now, Campbell is wary of Kaepernick – who threw for 398 yards last weekend, albeit playing catchup in a blowout loss to the Saints.

"They've gone through a lot of changes," Campbell said. "But I've played against Kap when he's done some special things. I respect him."

Kaepernick is barely completing 50 percent of his passes this season, and acknowledged injuries and other setbacks – he was embroiled in a battle over his contract for a while – have made it harder to return.

"Those are the flows in the division," Peterson said. "The table can turn at any given time."