SANTA CLARA – The only glitches in Levi's Stadium's NFL debut: There were a few traffic snarls getting to the game, the audio for the National Anthem was spotty and the grass on the field hasn't fully taken root.
Oh, and the home team appears to have suffered a major power outage.
The 49ers have managed just one Phil Dawson chip-shot field goal in their first two warm-up games and only sniffed the goal line on their final drive Sunday. They were stopped two yards short, and their Levi's house-warming party turned into a 34-0 rout at the hands of the Broncos.
After the game Jim Harbaugh said the team had plenty to “tighten down” before the all-important third preseason game on Sunday, but he said the execution was “off in little, correctable ways.”
“It's a guy here or a guy there,” he said of the mistakes. “We're taking turns with it. Can't really pin it on one spot right now.”
The one spot that will receive the brunt of the scrutiny is backup quarterback.
Starter Colin Kaepernick and the first-string unit, which included running back Frank Gore and receiver Michael Crabtree for the first time this preseason, certainly weren't perfect. But they gained five first downs and Kaepernick, who was in for two series, nearly hooked up with receiver Brandon Lloyd on a 37-yard touchdown toss that was just out of the diving receiver's reach.
For the second straight game, however, the offense disappeared as soon as Kaepernick left the game.
Blaine Gabbert's completion percentage improved a bit from the preseason opener against the Ravens, but he seemed content to throw short dump offs and slant patterns, most of them to rookie receiver Bruce Ellington. His first four completions were for three, three, one and four yards.
The only time he pushed the ball down field, to receiver Quinton Patton, the pass was picked off by Denver cornerback Tony Carter.
Harbaugh said Patton shared the blame and that the play was a microcosm of the preseason so far for the 49ers.
“I think (Patton) could have looked earlier,” he said. “We're off. We're that kind of off right now. It's little. It's correctable. It shows up. That’s football. It punishes mistakes. Rewards execution and precision. And we’re off right now. We’re not a precise team. And we’re being punished for mistakes.”
An underthrown Gabbert pass in Baltimore also was intercepted. Over the last two games – both of them against the opponent's second-string defense – Gabbert's passer rating is 17.9.
As was the case in Baltimore, the third quarterback into the game for San Francisco was Josh Johnson. On his first pass attempt, Johnson tripped while pulling away from the center, got up, scrambled and then was stripped of the ball.
In order to wrestle away the No. 2 job from Gabbert, whose $2 million salary is guaranteed, Johnson must make his case to Harbaugh and the 49ers' front office as plainly as possible. He didn't on Sunday, finishing 2-3 for nine yards.
The No. 4 quarterback, McLeod Bethel-Thompson, also committed a turnover when his fourth-quarter pass was intercepted at the San Francisco 23-yard line and led to Denver's final points of the game.
Even the 49ers' longest offensive play – a 48-yard pass from Bethel-Thompson to tight end Kevin Greene – glanced off of Broncos safety John Boyett's hands and probably should have been intercepted.
Harbaugh said he would not bring in outside help at quarterback. “Whoever doesn't turn the ball over will be the backup quarterback,” he said.
On defense, the 49ers again played without prominent starters, including linebacker Patrick Willis, cornerback Tramaine Brock and the entire starting defensive line. When Broncos quarterback Peyton Manning hooked up with tight end Julius Thomas on a 17-yard touchdown in the second quarter, only three of the 49ers' would-be Week 1 starters were on the field.
The biggest issue is on offense. The 49ers are scoreless in their last seven quarters, they've committed seven turnovers and have been outscored 57-3.
The best part of the game for the home crowd was the new stadium, and many patrons seemed more intent on exploring the new venue than watching the product on the field.
“It's a positive environment; they did a great job,” Gabbert said. “But we'd like to put our footprint on it with a win.”
Read Matt Barrows’ blogs and archives at www.sacbee.com/sf49ers .