SAN FRANCISCO -- If one decision summed up the 49ers' meekest offensive display under Jim Harbaugh's watch, it came 2 yards from the Carolina Panthers' end zone.
The 49ers, already with a 6-0 lead in hand in the second quarter, sent their offense onto the field and bluffed as if they were going for it on fourth-and-1. Instead, they opted for another Phil Dawson field goal and never again got closer to the goal line in a 10-9 loss Sunday that snapped a five-game win streak.
"We weren't running it," quarterback Colin Kaepernick said of the 49ers' fourth-and-1 intentions all along.
Did he lobby otherwise? "That's not my call," Kaepernick replied.
What unfolded was the lowest offensive output (151 yards) since Harbaugh took over as coach in 2011. Idle last weekend, the 49ers (6-3) fell 21/2 games behind the NFC West-leading Seattle Seahawks (9-1).
Harbaugh cited two of the 49ers' many casualties Sunday for why they bailed out on fourth-and-1 from the 2.
"We really were out of a couple personnel groups we would have liked to have been in in that situation," Harbaugh said. "Both (Garrett) Celek and Vernon Davis were out. We needed time to move personnel around to accommodate that situation."
Celek left with a first-quarter hamstring injury, Davis exited with a concussion two snaps before the fourth-and-1 call, and that left only one healthy tight end, Vance McDonald. The 49ers entered the game 6 of 8 on fourth-down calls, but without their regular two tight-end package, their power-run game apparently was put on hold.
Wide receiver Anquan Boldin called the 49ers' overall offensive display "unacceptable." They had just 46 net passing yards when factoring in Kaepernick's career-high six sacks.
Kaepernick was 11 of 22 for 91 yards, and his final pass resulted in an interception during what he called "desperation mode" for the league's worst-ranked passing attack.
As the 49ers' second-leading receiver, Davis' absence loomed large, and a reminder came when McDonald dropped a potential 35-yard pass at the Panthers' 25-yard line early in the fourth quarter.
"Vernon changes defenses," Kaepernick said. "He makes them adjust differently and do things they don't normally do. He's a big loss."
The 49ers defense admirably overcame its own war of attrition, losing safety Eric Reid to a concussion and defensive tackle Ray McDonald to an ankle injury. Among the unit's reinforcements was Aldon Smith, who returned from a five-game absence but played only 11 snaps, typically one or two a series in a pass-rushing role.
Linebacker NaVorro Bowman called it "stressful, knowing you're playing well but can't control the other side of the ball (with the 49ers offense)."
Third downs especially doomed Kaepernick & Co. They converted just 2 of 13 third-down opportunities, mirroring their 3-of-12 efforts in their losses to the Seattle Seahawks and Indianapolis Colts in Weeks 2 and 3.
"That's all on us," Boldin said. "We have a number of weapons on offense. We've got to do a better job of making it happen."
Caught on camera yelling after one of the 49ers' failed drives, Boldin disputed the notion he was directing his anger at Kaepernick. Boldin finished with three receptions for 23 yards, and Mario Manningham had three for 30 in his season debut.
The Panthers (6-3) won their fifth straight behind a solid defensive effort, timely offense and clutch special teams.
"They're a good defense, but today was more of our lack of execution than what they were doing," Kaepernick said.
Graham Gano's 53-yard field goal put the Panthers ahead 10-9 with 10:05 remaining.
DeAngelo Williams cut the 49ers' lead to 9-7 when he ran 27 yards for a second-quarter touchdown, avoiding potential tackles from defensive backs Carlos Rogers, Tarell Brown and Reid.
"It's just a sinking feeling right now," Harbaugh said. "You didn't get the job done as a team. We'll bounce back. We'll come storming back."
The 49ers play their next two games on the road, against the New Orleans Saints and Washington Redskins.
Said Bowman: "We can't keep giving wins away."
49ers (6-3) at New Orleans (7-2), 1:25 p.m. FOX
Ex-49ers star Terrell Owens, left, shown Sunday with Jim Harbaugh, was honored before the game. Read the full story at www.mercurynews.com/49ers.