Frank Gore was upset after Week 3, and everyone knew it. The 49ers were 1-2, and after averaging about two yards per carry in the 49ers’ first two games he was shackled by a pass-centric game plan against the Colts even though he rushed for 82 yards on just 11 carries.

Frank Gore 49ersJim Harbaugh has called Gore “a mystical man” on a few occasions. And when the 49ers’ leading all-time rusher is angry, he doesn’t yell or complain to the media. Anyone can see the agony on his face. No one on the team took the Super Bowl loss harder, no one has mentioned the goal of getting back and avenging that loss more often. Gore was mad, and several observers thought he was done. Then he went to St. Louis and rushed for 153 yards, his best game of the season when the 49ers needed it most.

On Sunday, we saw the same look of pained frustration we saw when the 49ers’ record fell to 1-2. But this time the 49ers were winning (barely) their sixth consecutive game. Gore was his regular dependable self as a pass blocker, but his rushing output (13 carries, 14 yards) was his lowest since the last game of the 2011 regular season when he rushed for 9 yards on 7 carries against the Rams.

First instinct is to look at Gore’s body of work — which includes 92 carries for 482 yards and four touchdowns in the playoffs — and start sending preemptive sympathy cards to the Green Bay Packers. But the Packers held Gore to just 44 yards on 21 carries in Week 1. The 49ers won that game by six points as Colin Kaepernick and Anquan Boldin took advantage of the Packers’ tunnel-vision approach to stopping the 49ers: keep the rushing yards to a minimum, both Gore’s and Kaepernick’s.

It seems obvious … stop the most run-happy team in the league from doing what they do best, reap the rewards. Only the 49ers averaged 101.8 passing yards per game in their four losses, 214.3 passing yards per game in their 12 wins. Six of Kaepernick’s eight interceptions took place during San Francisco losses. The 49ers won four of the five games in which they were held under 100 rushing yards.

There seems to be a direct correlation between keeping the 49ers’ passing attack under wraps and beating the 49ers.

So Green Bay is left with two choices: stack the box again and hope the game turns out differently, or focus on stopping Vernon Davis like they did a year ago in the NFC Divisional Round … when Gore gained 167 all-purpose yards.

The 49ers won’t plan on Kaepernick replicating his 412-yard Week 1 effort in temperatures less than 20 degrees, so the Packers are probably going to try to find a happy medium between stopping San Francisco’s offense on the ground and through the air. With Gore less than happy going into this game, shutting him down completely will be a difficult task.