Surprised Perrish Cox played so many snaps against the Packers? So was Cox, who thought he would get into the game for a handful of plays but ended up playing more than half of San Francisco's 61 defensive snaps.
The reason? Cox comes in for the 49ers' dime defense, which uses six defensive backs and which usually counters an offense that uses four wide receivers. The Packers went with four wide receivers a few times when Randall Cobb entered the game. But the reason the 49ers were in their dime package so much Sunday was that they wanted Cox, and not an inside linebacker, matched against Green Bay tight end Jermichael Finley, whom they considered the de facto fourth wide receiver.
"Some of those plays, we were treating Finley like a split-out receiver," Cox said. "So we were treating him like another receiver."
Whether the 49ers will be in their dime package as much this coming Sunday will depend on how often the Lions use four wide receivers (probably not very much) and how the 49ers view Lions tight end Brandon Pettigrew, who had 83 catches last season.
When the teams met a year ago, the 49ers played their nickel defense - in which both Patrick Willis and NaVorro Bowman are on the field - and Willis often was matched up with Pettigrew, who had eight catches for 42 yards and a touchdown. Then again, the 49ers didn't have Cox on the roster last year, and defensive coordinator Vic Fangio clearly likes to get Cox in the game.
As far as which upcoming opponents use four wide receivers ... the Bills, who visit Oct. 7, used that formation 333 times last season, according to Pro Football Focus, which was nearly one-third of their total plays. The Bears and Cardinals also were among the league leaders when it comes to four-receiver sets. Detroit didn't use it much at all, mainly because they like to have Pettigrew and/or a running back on the field.
One of the Packers' goals Sunday was to wear out defensive end Justin Smith. Mission unaccomplished. Smith played 59 snaps (penalties not included) due to a combination of the 49ers' defensive effort and long drives by the 49ers' offense. Last year, he averaged 58 snaps a game during the regular season.
-- Matt Barrows