The 49ers scoreless second half against the Panthers in their 10-9 home loss was possibly their worst offensive performance of the year. Quarterback Colin Kaepernick completed only 4 of 11 passes for 39 yards, an interception and was sacked three times.

Looking at the coaches tape, one would expect to find Kaepernick making bad decisions and inaccurate throws. However, the mistakes by the offense had less to do with the quarterback and more to do with the offensive line and the receivers.

Of Kaepernick’s 11 second-half attempts, seven were on target, two were dropped, and two were thrown away and one was intercepted on a desperation throw at the end of the game. Really, he only threw one bad pass in the second half, on a deep out cutting route to Anquan Boldin in which he threw into double coverage on a ball that should have been intercepted.

Throughout the entire game, Kaepernick was pressured and all of his sacks occurred in three seconds or less, meaning they were no coverage sacks.

The 49ers constantly yielded sacks and pressures mainly because of individual breakdowns in pass protection. Here’s a look at those responsible:

Joe Staley 2, Anthony Davis, 2, Mike Iupati 2, Jonathan Goodwin 1, Alex Boone 1, Frank Gore 1, Vernon Davis 1, well called blitz 1, wrong line shift on a blitz 1, linebacker not fooled on a bootleg pass, 1.

The offensive line was the main culprit for Kaepernick’s worst game of the season and they had a particularly tough time blocking defensive ends Charles Johnson and Greg Hardy.

Part of the offensive futility had to do with some players trying to do too much, and the greatest offender was wide receiver Anquan Boldin. Seeing tight end Vernon Davis left in the second quarter with a concussion and knowing that a hampered Mario Manningham, and the ineffective Kyle Williams were the only receivers left, Boldin went off-sides once and was called for offensive pass interference.

The last penalty negated a 14-yard pass to Manningham.

The Panthers also played eight in the box often when the 49ers had two receivers on the field, which is a personnel group where the offense is not favoring either run or pass. In 21 two receiver sets, the Panthers played with eight men up 15 times.

However, without Michael Crabtree and tight end Vernon Davis, the 49ers only real options out of two-receiver formations was to run most of the time.

Most defenses, even with Davis and Crabtree, play eight men up against the 49ers’ two-receiver formations. The only way to drag the eighth man out into coverage is to strike down the field with big plays. The 49ers never had a play over 20 yards against the Panthers in their regular season loss to Carolina.

In Sunday’s playoff game, the Panthers’ defense will likely beg the 49ers to throw deep. But that means the offensive line can not have individual break downs in pass protection and that Davis, Crabtree and Boldin will need to earn their pay checks.