GLENDALE, Ariz. -- Who are the real 49ers?
A.) The efficient squad that beat up the Vikings in Week 1, or
B.) The mistake-prone squad blown out by the Steelers in Week 2?
The 49ers are leaving little doubt about the answer in a first half that saw Colin Kaepernick throw three interceptions, two of them for touchdowns, and in which the 49ers defense, for the second straight week, hardly challenged the opposing passer. They trail 31-7 and look very much like the weak and wayward team they were in the Dennis Erickson and Mike Nolan eras.
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One of the few bright spots was a 37-punt return by Aussie Jarryd Hayne, who took a second-quarter punt on the run and reached the Arizona 19-yard line. That set up a 12-yard read-option run by Kaepernick, who scored only one touchdown on the ground all of last season.
On the 49ers' third play from scrimmage, Kaepernick threw off his back foot to tight end Vernon Davis. The ball was snatched instead by cornerback Justin Bethel, who easily ran in for a Cardinals touchdown.
The next drive was almost a carbon copy: Kaepernick wasn't sure where to go with the ball, was pressured in the pocket and threw to his right, this time to Anquan Boldin. Safety Tryann Mathieu was covering someone else on the play, but as the ball left Kaepernick's hand he left his many, stepped in front of Boldin and ran into the end at nearly the same spot Bethel crossed one drive earlier.
San Francisco seemed to get a bit of life when cornerback Kenneth Acker picked off Carson Palmer's pass deep in 49ers territory late in the second quarter. But Kaepernick gave the ball right back on a pass to Davis, who was well-covered by Mathieu and who had his second interception of the half. The Cardinals turned that gift into three points just as the first half expired.
The 49ers defense, meanwhile, didn't allow any long touchdowns like last week. But that's about the best thing you can say about the unit.
They also haven't disrupted Arizona's Carson Palmer and again have allowed an opposing receiver, this time Larry Fitzgerald, to run rampant in the first half. Fitzgerald has six catches for 99 yards. Palmer has 201 passing yards while running back Chris Johnson already has two touchdowns and 63 yards.