Cardinals Weigh In After 49ers Switch Back to Brock Purdy

Cardinals head coach Jonathan Gannon reacts to the 49ers’ switch back to Brock Purdy at quarterback, offering insight on why San Francisco’s offense remains so tough.

September 28, 2025; Santa Clara, California, USA; San Francisco 49ers quarterback Brock Purdy (13) during the third quarter against the Jacksonville Jaguars at Levi's Stadium. Mandatory Credit: Kyle Terada-Imagn Images | Kyle Terada-Imagn Images

ARIZONA -- The San Francisco 49ers are starting Brock Purdy at quarterback ahead of their duel in the desert against the Arizona Cardinals, though head coach Jonathan Gannon says much doesn't change for the team in their prep.

"He's a different player than Mac [Jones], but not a ton. I'm sure they had made adjustments to my eye. It's a Kyle Shanahan offense that's really hard to defend, and we're gonna have to be on it," said Gannon.

Jones has been the starter in San Francisco for eight of their ten games, which includes a Week 3 win over Arizona earlier in the season. Purdy has been battling a toe injury.

Regardless of who is under center for San Francisco, the 49ers will always be a tough call thanks to the presence of Kyle Shanahan, who is widely considered to be one of the top offensive minds in the game.

"One can copy ideas, but you can't copy the details. I would think that the details which his team plays with, jumps off the tape to me, at least. So everybody runs the same plays - it's what details can you get your guys to execute with," said Gannon.

"And the other thing about how they play, and why I have such a high opinion of Kyle is their play style jumps off the tape to me, all 11 guys. So their receivers block people and put major effort into blocking. They finish plays when they get their ball. Whoever's touching the ball, they're always finishing forward, challenging tacklers, never going out of bounds, never going down, always trying to gain extra yards.

"The quarterback carries out all his fakes, all the time. Like their play style, to me is top notch, really top notch. And it's one of the reasons, in my opinion, that they play really good offense and win, because of that."

Arizona has yet to win an NFC West game this season, and their chances of a victory moving into Sunday aren't viewed as likely as sportsbooks have the 49ers as favorites with a -2.5 point spread.

Many believe Jones is a better quarterback than Purdy at this point in time, though it's clear the Cardinals view San Francisco as such a well-oiled machine.

The change of Purdy back in the starting lineup won't change too much of what they're able to do.