The injury news for the Green Bay Packers was as bad as feared on Monday.

Outside linebacker Aaron Kampman and cornerback Al Harris have both been lost for the season with knee injuries suffered in Sunday's win over the 49ers, and both will have season-ending surgery, Head Coach Mike McCarthy confirmed.

The personnel losses leave the Packers without two of their most experienced and productive defenders as the team tries to make a push for the playoffs over the season's final six games. Kampman was leading the team in quarterback hits by a large margin and had been a stalwart against the run all year, while Harris regularly was matched up with the opposing team's No. 1 receiver and was quietly putting together a solid campaign.

"Both Aaron and Al have meant a lot to us and our football team," McCarthy said. "Both have over 100-plus starts. Just thinking about it walking down here after visiting with Aaron, not seeing 74 and 31 in the huddle, it's going to be different. But it's a challenge that our younger players, they're going to have to step up and get ready on a short week for Detroit."

And that is the immediate focus for the Packers - the game against the Lions on Thursday. Players feel bad for their teammates as individuals, but they can't let those emotions affect their thoughts and preparations as a whole moving forward, especially now that the team has won two straight games to thrust itself right into the thick of the NFC Wild Card chase.

"You don't want to sound cavalier about it, but you've got to go play," cornerback Charles Woodson said after the game Sunday. "Whoever is in that backup role, they have to work this week on a short week and being prepared to play on Thursday. We just have to keep rolling."

How exactly the Packers will go about replacing Kampman and Harris isn't entirely clear yet.

Rookie Brad Jones and veteran Brady Poppinga both took snaps in Kampman's spot after he left Sunday's game in the third quarter, and second-year pro Jeremy Thompson is another option, but McCarthy said the coaching staff is still working on its game plan.

Tramon Williams will take Harris' spot as a starting corner, just as he did last season when Harris missed four games with a lacerated spleen. But McCarthy wouldn't commit to a specific plan for the nickel and dime packages.

After Harris went down in the fourth quarter on Sunday, Jarrett Bush moved up from the dime cornerback spot to the nickel, and rookie Brandon Underwood took over in the dime. With cornerbacks Will Blackmon and Pat Lee already on season-ending injured reserve, there don't appear to be a whole lot of other options, though the plan may focus just as much around how much each package is used as which players are in which spots.

"That's really what we'll spend today going through," McCarthy said. "Obviously the game plan for the Detroit Lions will factor into a lot of our decisions in who plays and where they play."

A couple of players also could be signed to the roster, either from the practice squad or from outside the organization, but how much they could contribute immediately, and on a short week of preparation, seems dubious at best.

But McCarthy emphasized on Monday that he's not about to let all the uncertainty distract his team from the job at hand, which is to beat Detroit and get to 7-4 with a 10-day break before the next game, against Baltimore on Monday Night Football Dec. 7.

"You have to overcome injuries. It's something you can't control. We will step up," McCarthy said. "Our coaches need to be creative. These are challenges you don't always prepare for, from week to week.

"This is a challenge that we'll meet. You lose good players, and really you don't want to see the individual go through it. But as far as our football team, trust me, they're in here today, they're getting treatment, they've worked out, they're watching film, and we'll be ready for Detroit."

Nothing foreign about short week

Twice already in McCarthy's coaching tenure in Green Bay, the Packers have had to prepare on a short week for a Thursday game. Back in 2006, the Packers played the Vikings at home on a Thursday night in Week 16. Then in 2007, the Packers played the Lions in Detroit on Thanksgiving, as they will do this Thursday.

The Packers won both of those previous games, so McCarthy and many of his players have success to draw on.

{sportsad300}From a coaching standpoint, McCarthy said that his staff began preparing a game plan for Detroit last Friday and Saturday, after all the preparation for San Francisco was completed. McCarthy said he also took a larger game plan, volume-wise, into the 49ers game with the idea that he'd carry over some of it to the Lions game because there isn't the practice time available to start from scratch.

"You just have to get your work done," McCarthy said. "There is a lot of prep planning really from the support staff and the coaching staff that we feel like we're way ahead."

For the players, taking care of their bodies is the top priority. Monday is a rest-and-recovery day, with players getting treatment in the training room and watching film. Tuesday will feature a full-length practice, though it won't be in pads, and then Wednesday will have a short jog-through practice before the team flies to Detroit.

"You have to rely on players to do the mental preparation, because we're not going to get out on the field a lot," receiver Greg Jennings said. "We're not going to have a whole ton of reps, so we have to keep the game plan short and simple, sweet and to the point. We definitely have to do a lot of studying on film."

The Lions are an NFC North opponent, so there's plenty of familiarity, and the Packers did face the Lions earlier this season, shutting them out 26-0 back on Oct. 18. Detroit is coming off a thrilling, last-second 38-37 win over Cleveland, but a shoulder injury to rookie quarterback Matthew Stafford puts his status for the game in doubt. Stafford missed the first meeting with the Packers this season with a knee injury.

"We definitely have to watch and see what they do differently from the first time," Jennings said.

Injury update

Both the Packers and Lions filed an injury report on Monday even though neither team practiced. The practice designations are considered estimations as to player availability if there had been a practice.

The Packers obviously listed Harris and Kampman as out, while the following players also would not have participated: tackles Allen Barbre (ankle) and Chad Clifton (knee), running back Ahman Green (groin), defensive end Cullen Jenkins (ankle), center Scott Wells (knee) and Woodson (hip).

Considering Clifton, Jenkins, Wells and Woodson have all missed practice time on occasion to deal with various ailments but generally have been available to play, the report doesn't raise any unnecessary alarms. Barbre and Green missed Sunday's game against the 49ers with their injuries.

Listed as limited were running back Ryan Grant (neck), defensive end Johnny Jolly (back) and guard Josh Sitton (back), while full participants would have included linebacker Brandon Chillar (hand) and fullback John Kuhn (hand).

For the Lions, six players were listed as not participating: Stafford (knee/left shoulder), receiver Calvin Johnson (hand/knee), safeties Kalvin Pearson (hamstring) and Ko Simpson (knee), linebacker Ernie Sims (hamstring) and defensive end Dewayne White (toe).

Eight players were listed as limited: defensive tackle Joe Cohen (ankle), safety Louis Delmas (ankle), linebackers Jordan Dizon (neck) and Zack Follett (neck), defensive tackle Grady Jackson (knee), tackle Daniel Loper (back), running back Kevin Smith (hip) and receiver Derrick Williams (hip).