The Green Bay Packers and Philadelphia Eagles both saw massive surprises at quarterback last week.
As Green Bay's four-game win streak came to a stunning end after Aaron Rodgers went down with an injury, Philadelphia got back on track behind Nick Foles' historic performance.
Now, the Packers will try to recover behind a journeyman backup while the Eagles hope for an encore from Foles on Sunday in Green Bay.
It will mark just the third time in 372 games for the Packers (5-3) in which Brett Favre or Rodgers is not their starting quarterback. Seneca Wallace is expected to fill in for Rodgers, who said on his weekly radio show he suffered a fractured left collarbone on a first-quarter sack in Monday's 27-20 home loss to the Bears.
Green Bay had won 29 of its last 31 regular-season games at Lambeau Field.
"That's a significant injury," said Rodgers, whose 108.0 passer rating trails only Peyton Manning. "We'll know more about the severity and the timetable later this week."
While Rodgers is expected to miss just his second start since taking over for Favre in 2008, coach Mike McCarthy said his quarterback's season isn't over.
"I'm relieved, no doubt," McCarthy said. "How long? We don't have our hands around a timeline yet, but I know Aaron is very optimistic and he'll do everything he can to get back in a timely fashion."
For the time being, Green Bay will have to rely on Wallace, who is 6-15 as a starter and has lost nine of his last 10 with the most recent coming Jan. 1, 2012, for Cleveland. Wallace, who wasn't in camp with the Packers, was 11 of 19 for 114 yards with an interception and was sacked four times after relieving Rodgers on Monday. He lost his lone start against Philadelphia on Nov. 2, 2008, completing 44.8 percent of his passes.
Foles likely put an end to what has been a carousel at the position for the Eagles (4-5). He became the seventh player in NFL history to throw for seven TDs - and the only one with a perfect 158.3 passer rating - with a career-high 406 yards in a 49-20 victory at Oakland last Sunday. Philadelphia had managed 10 points in back-to-back losses.
Even if Michael Vick were healthy - he's still unable to practice due to a hamstring injury - coach Chip Kelly likely would have had a hard time sending Foles back to the bench.
Like his team, Foles has been much better on the road. He threw for three TDs and posted a 133.3 rating in a win at Tampa Bay on Oct. 13, then completed 11 of 29 passes for 80 yards in a 17-3 home loss to Dallas in which he suffered a concussion.
While the Eagles have dropped 10 straight home games but are 4-1 on the road this year, Foles is 0-4 in home starts but has won three straight outside Philadelphia.
"I think what happened in the Cowboys game was such a surprise to everybody because that's not what Nick expects out of himself, not what we expect out of him," Kelly said. "I thought that what happened in the Cowboys game was an exception, not the rule. That's not the Nick Foles I know."
Foles found five different players for scores against the Raiders, including Riley Cooper for three. Cooper has caught 17 passes for 360 yards over his last four games.
Sunday's matchup will feature two of the league's top running backs in LeSean McCoy and Eddie Lacy. McCoy ranks first with 777 rushing yards on the season but just 147 in the last three games, while Lacy's 545 since Oct. 1 are the most during that span.
Lacy's 596 rushing yards as a rookie are already more than any Packer totaled in either of the last two seasons. He's averaged 23.8 carries over the last five games - a number that could increase should the Packers lean on their running game more with Rodgers sidelined.
Green Bay ranks fifth in run defense at 94.5 yards per game, while Philadelphia gave up 210 yards on 33 carries to Oakland last week.
The Packers won't see the return of tight end Jermichael Finley this season after placing him on injured reserve Tuesday. Finley will wait until 2014 to try to return from a spinal cord contusion suffered Oct. 20 versus Cleveland.
They do hope to have Clay Matthews, who is practicing this week with a club on his hand after having pins removed from his injured right thumb. Matthews, who hasn't played since an Oct. 6 win over Detroit, said he thinks he can play.
His brother, Casey, is a linebacker for Philadelphia.
The Eagles are 4-16 all time at Green Bay.