Blaine Gabbert's job security declines in defeat

SANTA CLARA, Calif. -- Quarterback Blaine Gabbert had another rough game for San Francisco on Thursday night in a 33-21 loss to the Arizona Cardinals, and 49ers fans at Levi's Stadium voiced their displeasure.

Midway through the second half, the crowd started chanting for backup Colin Kaepernick to replace Gabbert, who finished the game.

After the loss, 49ers coach Chip Kelly initially sidestepped a question about whether he would consider changing quarterbacks for the Oct. 16 game against the Bills in Buffalo.

"I don't think we're going to talk about that tonight," Kelly said.

Kelly, however, later acknowledged that he would use the 10 days between games to assess every aspect of his team.

"We're 1-4. We're going to look at everything," Kelly said. "We have to make sure we're giving our team the best chance to go out and win."

Gabbert completed 18 of 31 passes for 162 yards and one touchdown with two interceptions that led to 10 Arizona points. He had a passer rating of 56.1 on Thursday and has an overall rating of 69.6. Gabbert also ran 10 times for 70 yards and a touchdown against Arizona.

"I had two crucial turnovers that led to points for the Cardinals, and that was the difference in the game right there," Gabbert said. "I have to do a better job protecting the football and leading the team to more points to win games.

"I've got to play better. There's no question to that. I've got to do a better job of leading this football team, executing the offense, scoring points, winning games, the whole nine yards."

--The Cardinals played most of the second half without starting right guard Evan Mathis and starting left guard Mike Iupati, who left the game with ankle injuries. Earl Watford replaced Mathis, while John Wetzel replaced Iupati, and Arizona's running game kept rolling.

David Johnson rushed for 92 of his 157 yards in the second half. He capped a 12-play, 76-yard drive with a 1-yard touchdown run with 4:44 left, increasing Arizona's lead to 31-14.

"They did a heck of a job in that long drive running the ball," Arizona coach Bruce Arians said of Watford and Wetzel.

Mathis aggravated a previous injury, according to Arians, who was unsure how long either injury guard would be sidelined.

"Evan's got the same foot, but we don't know how severe it is, and the X-rays are still a little cloudy on Mike's leg," Arians said.

--Cardinals backup quarterback Drew Stanton filled in for Carson Palmer (concussion) and started against the 49ers for the third time in his 10-year NFL career.

Stanton started for Detroit against the 49ers on Dec. 27, 2009, in a 20-6 loss, completing 11 of 21 passes for 130 yards with three interceptions. He started against San Francisco again on Sept. 21, 2014, for Arizona in a 23-14 win, completing 18 of 33 passes for 244 yards with two TDs and no interceptions.

Then on Thursday night, he led Arizona to another victory against San Francisco. This time he went 11 of 28 for 124 yards and two touchdowns with no interceptions.

Stanton started a game for the first time since Dec. 11, 2014, a 12-6 Cardinals victory at St. Louis.

"I think just throughout the course of the game you have to find that rhythm," Stanton said. "I haven't been out there for a while in a game of this magnitude. It's a two-year break since I was out there."

Stanton threw both of his touchdown passes to wide receiver Larry Fitzgerald.

"Drew did a great job today of getting us in the right plays, being a real sparkplug, inspiration in the huddle for guys," Fitzgerald said. "We really fed off his energy. He made some great throws."