GREEN BAY, Wis. -- After their big win over the Dallas Cowboys last week, the question on Sunday was would the Green Bay Packers have a letdown or could they keep the momentum going.

The Packers held on protecting a 20-point first-half lead, but the bad news is that the injury bug might have bitten the green and gold again this season. And the latest bite may be the worst yet. The defense lost Aaron Kampman and Al Harris in the second half, both leaving with knee injuries.

"That is a huge blow to our team," said cornerback Charles Woodson. "I do not know the extent of their injuries but (Kampman and Harris) are important."

"We will not have all the information until (Monday)," coach Mike McCarthy said. "Both injuries did not look very good. There is some concern, but we'll have all the information (Monday)."

But, the Milwuakee Journal Sentinel reported that Kampan tore his ACL and will be out for the season. The website Nationalfootballpost.com is reporting that Harris also tore his ACL and will be out for the season. The Packers have not cofirmed either injury is season-ending.

"We can't dwell on the injuries to our veteran players," said rookie linebacker Clay Matthews. "We have younger guys that can step up and we are excited for that opportunity."

There was some good news for the Packers. Aaron Rodgers made San Francisco pay for a draft-day snub in 2005 and the Green Bay Packers survived a second-half surge by the 49ers for a 30-24 victory Sunday. The Packers (6-4) won their second straight game, rebounding from a midseason skid to emerge as a solid playoff contender going into their Thanksgiving Day date at Detroit.

"We played like our backs were against the wall," said Packers receiver James Jones. "And we want to make a deep playoff run so its each play is important."

Rodgers threw touchdowns to Greg Jennings and Jordy Nelson, and Ryan Grant rushed for 129 yards and a score. Sunday has rushed for 100 yards or more 11 times in his career.

"I felt good," Grant said. "I am healthy and we feel good as a team. It's a short week we just need to keep this going."

San Francisco quarterback Alex Smith recovered from a rough start to make things interesting with three second-half touchdowns, including rookie Michael Crabtree's first career score, but it wasn't enough for the 49ers (4-6).