Aaron Rodgers' calf is Sunday's wild card.
Based on what medical experts know about calf strains and how easily Rodgers aggravated his against the Detroit Lions two weeks ago, we have to assume Rodgers' mobility will be compromised against the Dallas Cowboys and likely as long as the Packers are in the playoffs.
Maybe he'll venture out of the pocket some, but chances are he'll be limited to sliding around in the pocket and throwing the ball away when pressured. That deprives the Packers of one of their best weapons: Rodgers' ability to make plays on the move, either with his league-best accuracy while throwing on the run or keeping drives alive with scrambles.
So is this a huge and perhaps fatal blow to the Packers, who are facing one of the NFL's hottest teams Sunday in the divisional round of the playoffs in the Cowboys? Maybe, though a scout from the Cowboys' NFC East Division says no.
"(The Packers) still are going to run the play action game," the scout said. "They're still going to put (Rodgers) in the shotgun or pistol. It's going to be about can the Cowboys win on the outside?"
By the outside, the scout means, can the Cowboys' top three cornerbacks (Orlando Scandrick, Brandon Carr and slot back Sterling Moore) cover well enough against Packers receivers Jordy Nelson, Randall Cobb and Davante Adams for Dallas to win? And the scout's guess is that no, the Cowboys don't cover well enough to prevent Rodgers from exploiting favorable matchups.
"I guarantee you Carr is the one Rodgers is going to try to find," the scout said. "He's just not very good. He's being more aggressive and all that, but he's just not very good. Teams are throwing at him more."
The scout has broken down the game tape of every Cowboys game this season as well as four Packers games. In an extended interview this week he agreed to assess the matchup and compare the teams' strengths and weaknesses.
He predicted a Packers victory but didn't dismiss the Cowboys' chances if they can keep the game close.
"(The Cowboys) are better than Carolina, and they beat Seattle," he said. "I don't think they're better than Seattle, and I'd probably say they're not as good as the Packers. This will be an interesting game. If they can hold up and stay in the game, they believe they can win a game at the end."
On offense, the Cowboys have plenty of weapons in the passing game but are likely to try to control the game on the ground. They have the NFL's leading rusher in DeMarco Murray (1,845 yards, 4.7-yard average per carry), the No. 2 rushing offense overall and maybe the best offensive line in the game.
In December, Bill Polian, the former general manager of the Buffalo Bills, Carolina Panthers and Indianapolis Colts, told Press-Gazette Media he considered Murray one of the NFL's three legit MVP candidates and that Murray is the league's fastest back to the hole. Murray is playing with a broken hand sustained four weeks ago, but it doesn't appear to be an issue. His 449 touches, fifth most in NFL history, might be.
"I think the season is finally catching up to him," the scout said. "He's hitting the holes, but not with the power of Week 6 or 7 or 8."
However, the scout said the Cowboys are deeper at halfback than they might appear, and that backup Joseph Randle (343 yards rushing, 6.7-yard average) could be a key player in a limited role. In the Cowboys' Week 6 upset win at Seattle, Randle gained 52 yards on five carries.
"Randle is more explosive," the scout said.
One key will be the Packers' defensive personnel defending the run.
Since defensive coordinator Dom Capers' decision to move Clay Matthews from outside linebacker to inside linebacker in place of A.J. Hawk in the nickel, the Packers' run defense is giving up 86 yards a game, which is sixth-best in the league over the second half of the season. They were last in the league before the move, which included playing second-year pro Sam Barrington at the other inside linebacker spot and Micah Hyde extensively as the nickel cornerback because of his tackling skills.
However, the Packers have faced only one team in the top 10 in rushing in the second half of the season, Philadelphia at No. 9. And really, there are only two superior running teams in the league, Seattle and Dallas.
The question is whether Capers will take the next step and replace Hawk with Matthews in the base defense as well, some or even all of the time. That would weaken the Packers' outside pass rush in that personnel group but improve their chances of containing the run.
The Cowboys can dictate the Packers' personnel with their offensive packages. If Capers stays with Hawk in base personnel and the Cowboys like that matchup, they can play their two tight end package extensively. It's a regular part of their offense, and Capers almost always matches two tight end sets with his base 3-4.
"They'll get in two or three tight end packages and hammer the ball," the scout said. "Other than Arizona and Detroit, they've run the ball really well on people. They took it to Seattle and ran the ball, and that was the difference in the game."
If the Cowboys run the ball well enough, that opens everything for quarterback Tony Romo, who led the NFL in passer rating (113.2). Murray's big season and Romo's great numbers (34 touchdowns, nine interceptions) aren't coincidental. As he's always been, Romo is at his best outside the pocket.
"When they stay ahead of the chains, when they're second-and-5 or second-and-4, he's tough to stop," the scout said. "He can really get it going, and he has all year, especially the month of December. I thought the (42-7 win) against the Colts, he came out and went after them. I don't doubt he'd do the same thing against the Packers. "
The scout said he expects the Packers to match up with Cowboys receiver Dez Bryant the same way they did against Detroit's Calvin Johnson in the regular-season finale. In that game, they covered Johnson with whichever cornerback (Sam Shields or Tramon Williams) lined up on his side of the field. They usually kept one safety deep and regularly played the other, usually Morgan Burnett, near the line of scrimmage to play the run.
The scout described receivers Terrance Williams and slot man Cole Beasley as good complements to Bryant — Williams is at his best finding space when Romo scrambles, and Beasley is quick enough to get open on underneath routes. But the toughest matchup might be tight end Jason Witten, who at age 32 is second on the team with 64 catches.
Capers often uses a combination of linebackers and safeties to cover good receiving tight ends. Hyde, the nickel back, might be the Packers' best matchup.
"Witten's not fast, but he gets open," the scout said. "I'm not sure they're going to be able to cover him."
When the Packers have the ball, the big question is how much Rodgers' injury will change the way both teams play.
To help protect Rodgers, coach Mike McCarthy might run halfback Eddie Lacy more against a Cowboys defense that ranks No. 8 against the run, No. 19 in total yards and No. 15 in points.
"You can't let Lacy get going downhill against you," the scout said. "In the Buffalo game they ran weak-side plays where he was physical. In the Detroit game, they ran some physical plays. You've got to get people up on him and make him have to stop and start.
"I could see the Packers coming out and saying, 'We're just as scared of your offense as you are of ours. So we're going to play ball control.'"
Then there's the question of whether Cowboys defensive coordinator Rod Marinelli will be more willing to rush Rodgers hard because of the quarterback's limited mobility. Most teams the second half of the season have tried to contain Rodgers in the pocket more than sack him, and the scout guessed the Cowboys will do the same despite the injury.
That's mainly because with DeMarcus Ware departed in free agency in the offseason, the Cowboys lack a top pass rusher and don't rush well (No. 28 in the league in sacks percentage).
Their most talented rusher, end Anthony Spencer, had only a half-sack in 13 games this season after undergoing microfracture surgery in 2013. But last week against Detroit he had a sack, and the scout said Spencer recently has looked a little more like the Pro Bowl player he was in 2012. He'll be matched against right tackle Bryan Bulaga.
The Cowboys' other end, Jeremy Mincey, is expected to play after sustaining a concussion last week. He's a power rusher at 6-3½ and 272 pounds, which might have given left tackle David Bakhtiari more trouble last year as a rookie than after he added strength in the Packers' offseason workout program last spring and summer.
"The Packers are good enough to block them," the scout said. "It's just a matter of, can the Cowboys get anybody home to make Rodgers move and make that calf lock up a little bit?"
Marinelli doesn't blitz much, and the scout doubted he will in this game either because Rodgers excels against the blitz (a 127.1 rating, according to ProFootballFocus).
"They never get anybody home," the scout said. "So they might as well rush four and play coverage behind it."
One of the Packers games the scout watched was Buffalo, which defeated the Packers and held them to 175 yards passing four weeks ago. The Bills have a good front four, and their secondary's physical coverage disrupted the timing of the Packers' routes.
But the Cowboys might not have the personnel to pull it off.
"Moore will be physical, and Scandrick will be physical," the scout said, "but Carr won't be physical."
The Cowboys' biggest problem defensively is that they've relied heavily on turnovers. Their 31 takeaways (18 interceptions, 13 fumbles) rank No. 2 in the NFL.
But this week they're playing a quarterback who rarely turns the ball over. The scout was so intrigued by Rodgers' incredible streak of not throwing an interception at home since Dec. 2, 2012 against Minnesota that he went back and looked at the play.
He was amazed to see that interception came not on a regular throw but a gimmick play in which Cobb took a toss to his left and threw back to Rodgers, who then tried to hit Greg Jennings downfield in double coverage. Vikings safety Harrison Smith intercepted.
"(The Cowboys) create a lot of turnovers," the scout said. "The problem is, that guy hasn't turned the ball over at home in what, three years? If you're thinking he's going to throw interceptions, that's a problem."
— firstname.lastname@example.org and follow him on Twitter @PeteDougherty.