SAN FRANCISCO (AP) - Clay Matthews and the Green Bay defense spent a good chunk of the offseason focused on figuring out how to stop the read option and defend mobile quarterbacks like San Francisco's Colin Kaepernick.
Kaepernick left that much of a mark on the Packers' embarrassed unit in a 45-31 divisional playoff loss to the 49ers at Candlestick Park in January. Now they meet again in a second straight season opener between a pair of NFC powers.
``I'm sure they've been game-planning for us since training camp,'' 49ers tight end Vernon Davis said. ``Any time you lose a game like that, you should be very mad.''
Kaepernick rushed for a quarterback-record 181 yards and two touchdowns and threw for two more TDs.
The Packers have been forced to relive the game in the film room this week - even if many of Green Bay's players weren't part of it.
``It was a disappointing night for us,'' quarterback Aaron Rodgers said.
Kaepernick, for one, has vowed to forget about that impressive playoff debut eight months ago.
``We're not worried about what happened last year,'' he said.
The Packers have no choice but to be worried. They were embarrassed by the NFC champions in their opener last year at Lambeau Field, then again in the postseason.
Here are five things to watch in Sunday's Week 1 NFC showdown and rematch of the divisional playoffs:
TWO NEW TACKLES: Rookie left tackle David Bakhtiari and inexperienced starting right tackle Don Barclay are being counted upon to fill huge holes in Green Bay's offensive line. They face the daunting task of protecting Rodgers against one of the best defensive fronts in football.
Rodgers' simple message: ``Block those guys, please.''
Bakhtiari took over after left tackle Bryan Bulaga was lost to a season-ending knee injury early in training camp, while Barclay beat out veteran Marshall Newhouse for the other spot.
``Their front seven is a big challenge all the way through,'' coach Mike McCarthy said. ``It's definitely something our young guys have been preparing for.''
The 49ers expect Rodgers to release the ball even sooner to take some pressure off the O-line.
``They've got a $100 million quarterback - we know they're going to want to throw the ball,'' 49ers linebacker Patrick Willis said.
Willis, meanwhile, is scheduled to play as he recovers from a broken right hand.
KAEPERNICK'S TOP TARGET?: Anquan Boldin makes his 49ers debut as San Francisco's projected top wide receiver for Kaepernick. Everybody involved hopes Boldin, Davis and a healthy Kyle Williams can pick up the load with 2012 top wideout Michael Crabtree sidelined until at least November recovering from a torn right Achilles tendon that required surgery.
Boldin, who beat San Francisco in the Super Bowl with Baltimore, and Davis expect productive years alongside the athletic, strong-armed Kaepernick in his first full season as starter.
``The chemistry that we're building, the brotherhood that we've put together, it's impeccable,'' Davis said. ``It's amazing that you come in here each and every day and be able to work with a guy like Kaepernick.''
GREEN BAY RUNNING GAME: McCarthy has faced question after question about his running game.
Now, all eyes will be on rookie Eddie Lacy to see whether he can back up his coach's confident stance - against stingy, run-stopping San Francisco, no less.
Lacy and Johnathan Franklin were drafted to improve Green Bay's backfield. The Packers cut ties with 2012 top rusher Alex Green.
Former Alabama star Lacy carried 204 times for 1,322 yards and 17 touchdowns last year.
REID'S MOMENT: With hard-hitting rookie free safety Eric Reid earning a starting job, the 49ers have the chance to redeem themselves after last year's debacle with top draft pick A.J. Jenkins, who didn't catch a pass and was traded last month to Kansas City.
San Francisco selected Reid with the 18th pick of April's draft out of LSU. He replaces departed star Dashon Goldson.
``The first day I got here, it was a lot faster than college and the defense was tougher, but it just takes practice and repetition,'' Reid said.
HELPFUL INTEL ON THE 49ERS: The Packers picked up a pair of former 49ers quarterbacks just in time for Week 1: Seneca Wallace and Scott Tolzien.
More so than Wallace, who spent only a week in San Francisco's system, Tolzien could provide some valuable insight into the 49ers' schemes and playbook.
Jim Harbaugh acknowledges the issue, though he noted ``danger is not the word I would use'' in describing the potential advantage for the Packers.
``Our plan remains the same,'' Harbaugh said. ``There's things he knows. We'll see how that plays out.''
In fact, Matthews said he would try to find an hour of time to connect with Tolzien before game day.
AP Sports Writer Genaro C. Armas in Green Bay, Wis., contributed to this story.
AP NFL website: www.pro32.ap.org