Personnel report: 49ers' vs. Aaron Rodgers

Vic Fangio, the San Francisco 49ers' defensive coordinator, knows what his team's up against when facing Green Bay Packers quarterback Aaron Rodgers on Sunday.

"A great way to explain him is, he's Drew Brees with great scrambling ability and actually a little stronger arm," Fangio said.

The 49ers will combat the Packers' passing game with a strong pass rush and a slightly reconfigured secondary. Newcomer Perrish Cox could join fellow cornerbacks Tarell Brown, Carlos Rogers and Chris Culliver in the 49ers' dime defense.

"They will dictate what kind of game it is from a personnel standpoint," Fangio said. "We are prepared to match their personnel with our people and we're a little different than some people in that we will keep our base defense out there against three wide receivers."

That last comment caught my attention. The Packers used three wide receivers on greater than 60 percent of Rodgers' pass attempts last season. While the 49ers have sometimes remained in their base defense against three-wide personnel, that has been the exception.

The first chart shows how the Packers' three-receiver offense has fared against various defensive personnel over the past three seasons. "Small" personnel represents groups with at least one additional defensive back.

The totals in the first chart include 12 pass plays against the 49ers in 2010, before Fangio and the current staff was in place for San Francisco. The 49ers collected two sacks on those plays. Greg Jennings also beat the 49ers for a 57-yard touchdown on one of those plays, with Reggie Smith and Dashon Goldson as the safeties.

The second chart shows how the 49ers' defense fared, by personnel, against three-receiver offenses for last season only.

The 49ers played their base defense most extensively against the three-receiver groupings of Seattle (10 plays) and Arizona (seven), generally with positive results. The Cardinals' Larry Fitzgerald did strike for a 17-yard gain in Week 14. Seattle's Doug Baldwin managed a 13-yard reception on a first-quarter screen in Week 16.

Again, I would expect the 49ers to generally rely upon their sub packages against the Packers' three-receiver groupings. We'll have to see how they fare if and when they do play their base defense in these situations. Their base pass rush should improve now that the team plans for Aldon Smith to be an every-down player, not just a situational rusher.

Note: ESPN Stats & Information provided the play-by-play data for both charts.