GREEN BAY, Wis. (AP) -- Charles Woodson isn't worried, even if Sunday's season-opening loss didn't offer clear-cut evidence that the Green Bay Packers' efforts to beef up their defense made much of a difference.

Woodson says it will take some time for the Packers' new players to make an impact, and the veteran defensive back insists he saw signs of progress in a 30-22 loss to San Francisco.

After allowing more yards than any other defense in the league and giving up way too many big plays in 2011, the Packers used their first six draft picks on defensive players and did a little more shopping in the free-agent market than they typically have under general manager Ted Thompson.

But the revamped defense still gave up 377 yards to the 49ers, who looked more explosive on Sunday than they typically did during last season's run to the NFC championship game.

Alex Smith was 20 of 26 for 211 yards with two touchdowns and no interceptions, and Frank Gore ran for 112 yards and a touchdown.

Things don't necessarily get easier this week, with the Chicago Bears bringing new wide receiver Brandon Marshall to Lambeau Field on Thursday night.