By Morris Phillips

Maybe it was just the 49ers heeding the new NFL in-stadium bag policy.

One plastic bag no more than a foot in length, hardly big enough for a player to pack his “A” game, instead containing a clearly visible game plan all the better for the opponent to quickly dissect.

What else would explain a team expected to compete for a Super Bowl berth getting embarrassed in front of a rare, hyped-up sellout pre-season crowd, 34-0 in its first game at a spanking new stadium?

Well, the 49ers arrived too early to get stuck in traffic, and Peyton Manning may have been in regular-season form, but he played just two series. Six San Francisco defensive starters didn’t play, but that does excuse the other five. And two interceptions and two fumbles won’t cut it for a Jim Harbaugh-coached team.

49ers TV analyst Tim Ryan felt the 49ers appeared physically spent, coming off an extended weekend in Baltimore where they scrimmaged with the Ravens daily and then took two days off from practice upon returning to the Bay Area.

Whatever caused the team’s second straight desultory exhibition performance wasn’t going to send Harbaugh searching for explanations. Instead he made it clear he needs the football team he was expecting to coach to show up for work, starting this week.

“We need improvement,” Harbaugh said. “And we need to make decisions on who we’re playing with. We’re not going to keep experimenting. We got to tighten this down fast.”

For the second straight week, the 49ers allowed their opponent to run too many plays and gain too many yards. Early the presence of Manning–running a quick hitter attack–put the 49ers’ young interior linebackers Michael Wilhoite and Chris Borland on their heels. In the absence of sidelined All-Pro NaVorro Bowman, one of the two figures to start opposite Patrick Willis, but none of the three can give the team the playmaking ability that Bowman possessed. The secondary also lacked the needed playmaking to counteract Manning, who completed all eight of his pass attempts on his second series, which culminated with a 17-yard Julius Thomas touchdown catch and a 10-0 Denver lead.

Colin Kaepernick looked good in his limited time, completing 5 of 9 attempts, but missing on a deep ball intended for Brandon Lloyd. All signs point to Kaepernick continuing his upward arc in his second, full-season as starter, but on Sunday mistakes cropped up and the offense could only muster a missed Phil Dawson field goal attempt during Kaepernick’s time in the game.

“I should have hit a few more throws today but I think our offensive line is playing well and our running backs have run well,” Kaepernick said. “We just have to finish our drives off.”

Backup Blaine Gabbert is due $2 million this season but he hasn’t distinguished himself with his play with two poor pre-season performances along with his spotty play in the team’s practices. On Sunday, Gabbert took over for Kaepernick and played into the third quarter, but threw for just 40 yards and one pick.

Among those that stood out offensively were rookies Bruce Ellington and Carlos Hyde. Michael Crabtree made his pre-season debut as did Frank Gore, though both appearances were brief.

In the second half, the 49ers coughed the ball up three times as the Broncos increased their 17-point halftime lead. When the 49ers did move the ball, the ending wasn’t the desired one.

Kicker Phil Dawson missed from 55 yards on the game’s initial possession, and then again early in the second quarter.

The two teams meet again on October 19 in Denver which undoubtedly contributed to the bland nature of the game plans. Still, the bottom line was the 49ers wanted to look and play better.

“You put a lot of thought into anything you do,” offensive tackle Joe Staley said. “Anytime you step on the football field you’re trying to put your stamp on what you do and how you perform, so you take care of your business and do as best as you can. I don’t think there’s any, ‘well it’s pre-season.’ It all means something.”

The 49ers get their second chance to endear themselves to the Levi’s Stadium crowd when the San Diego Chargers visit.