Jacobs and NFC West short-yardage guys

Peter from Rutland, Vt., points to Anthony Dixon's failed third-and-1 rushing attempt in the NFC Championship Game as one reason the San Francisco 49ers might have signed former New York Giants running back Brandon Jacobs.

This play escaped my attention in the Jacobs item Tuesday. I suspect the play-by-play file I consulted did not encompass the NFC Championship Game.

Rushing, 3rd- or 4th-and-1

"Dixon got stuffed by the Giants on a key third-and-1 attempt," Peter recalled. "He danced instead of smashing. That's why they took a chance on Jacobs. Dixon is not a reliable power back."

Perhaps, but Jacobs failed to convert a fourth-and-1 rushing attempt in the same game, and he has never been known for his hard-nosed running.

Dixon converted both of his rushing tries during the regular season when needing a single yard on third or fourth down. He missed that one attempt during the postseason, but Jacobs converted only 4 of 8 regular-season tries and 5-of-11 overall when counting the postseason.

I went back and watched Dixon's failed play just to be sure what happened. Dixon did not set a new standard for powerful running on the play, but neither did he have much room to run.

The 49ers shuffled their offensive line and brought onto the field two defenders, Justin Smith and Isaac Sopoaga, for additional blocking. The line, left to right, featured Vernon Davis, Alex Boone, Adam Snyder, Jonathan Goodwin (center), Mike Iupati, Anthony Davis, Joe Staley and Smith. Sopoaga lined up to the right in an offset-I formation.

The blocking was not very good. Mathias Kiwanuka shed Smith immediately and blocked Dixon's path off tackle. Chris Canty got between Anthony Davis and Staley in time to affect Dixon. Dixon did hesitate and step to the side as he sought an opening. Again, though, the blocking was not great.

While an NFL offense should be able to pick up a third-and-1 on the ground, I've thought the 49ers needed to occasionally break from tendency in these situations, not just with a pass but with a deeper strike to Vernon Davis. Previous 49ers coaching staffs succeeded with this tactic.

The 49ers had beaten the Giants for an 18-yard pass to Delanie Walker on a third-and-1 play when the teams met back in Week 10. Perhaps the 49ers' staff knew the Giants would be ready if they tried another pass. And, as noted, the team should be able to pick up a third-and-1 rushing play.

But with such a heavy formation to the right side, the Giants were ready for Dixon. They also took advantage of the fact that Smith, though a great player, plays defense and isn't a polished blocker.

The chart shows 2011 regular-season conversion stats for NFC West running backs on third and fourth downs with 1 yard needed for a first down. There's a reason teams use quarterback sneaks.