Anthony Davis Alex Boone 49ersThe 49ers’ offense has come under some heavy, perhaps undue criticism lately. After all, they are the NFC’s second seed and enjoying a bye during wild-card weekend. Long gone are the Jim Hostler-Jimmy Raye days, when San Francisco’s offensive game plan was pretty simple: run up the middle, run off tackle, incomplete pass, punt.

You know things have changed when people are actually calling  for the 49ers to run the ball MORE. It’s certainly no indictment on Colin Kaepernick’s ability to throw the ball, but an offense that passes too often can be just as vanilla as one featuring too much ground game.

Maybe the 49ers are really missing Kendall Hunter, although LaMichael James has been comparable in his performance as a replacement. The real issue seems to be Frank Gore, who was averaging nearly 5.7 yards per carry coming into Week 12 and has posted a modest 3.98 YPC since. The lowlight of Gore’s season was the six carry, 28-yard disappearing act in Seattle, although the 49ers did abandon the run quickly after facing an early deficit.

What seems more troubling is the 49ers inability to establish their running game on early downs. Facing the Cardinals on Sunday, Greg Roman called 11 runs to Frank Gore on first down. The first three went for two yards, one yard and no gain respectively, and all three of those drives were three and outs. In total, Gore averaged 2.63 yards per carry on first down, which doesn’t bode well for an offense that already has trouble converting downs and keeping drives alive.

East Bay Sports Guy already had an interesting take on whether or not Frank Gore is wearing down, and if fatigue is indeed the culprit then this bye week is more important than we thought. Film from the Cardinals game points to a different cause for the troubles in the run game, however.

8:57 1st quarter — 1st and 10

Gore run 1

The 49ers’ first possession was a total loss after being backed up on their own 1-yard line, so I went ahead and skipped looking at it and moved on to their second drive. Here is a look at Frank Gore’s first down run, designed to have a hole open between Anthony Davis and a flat-blocking Bruce Miller. The breakdown comes from both Davis, who can’t manage to get a push on his block, and Alex Boone, who misses his down block on the inside linebacker completely. You can see that Boone is already out of position in this shot (he should have leverage on the outside shoulder of his assignment, pushing him towards the numbers), and as a result the linebacker is able to keep Gore from getting to the second level.

Without any push from Anthony Davis, Gore’s cut comes too close to the line of scrimmage and he trips on his lineman’s foot. By the time he regains his footing, there’s nowhere for him to go.

10:57 2nd quarter — 1st down

Gore run 2

Here is a similar play call on a second quarter first down, except this time it’s on the opposite side of the formation. Bruce Miller scrapes across the line of scrimmage to push out the outside linebacker while Mike Iupati and Joe Staley open up the other side of the hole. The key to this play is Iupati shedding the defensive tackle to down block the inside linebacker. Once Iupati sheds him, Staley should have a good angle to block the tackle out. Instead, Iupati gets held up at the line of scrimmage, leaving Daryl Washington unblocked to stuff Gore for no gain.

That looks like defensive holding to me, but let’s be honest: defensive linemen get away with this play all the time. It’s a big reason why Justin Smith is so important to the 49ers.

11:00 4th quarter — 1st and 10

Gore run 3

Now for a first down run that worked… kind of. San Francisco is going to run Gore off of right tackle out of the I-formation, and unlike the other plays that I documented he’s going to gain six yards. That’s a pretty good gain considering how poorly the 49ers did on first down otherwise, except this run could have been a touchdown if not for another missed block from Alex Boone.

I hate to pick on the young guy, but these kinds of blocks have to be made. In the above screenshot Boone is chipping the tackle. His next step is to disengage and block out the inside linebacker. Everyone else on the right side handles their assignments, but Boone misses Washington again.

Although the 49ers’ offensive line has been considered one of the league’s best in terms of run blocking, it seems to be playing a big role in Frank Gore’s drought lately. The biggest concerns lie inside of the tackles, with Iupati and Boone seemingly incapable of holding blocks on linebackers. Even with Michael Crabtree’s arrival in the passing game, the 49ers’ bread is still buttered by running the football, and the line will have to improve by the time January 12th rolls around.