Last season, the Packers held up fairly well without Matthews for four games, going 3-1 during that span (Weeks 11-14). However, the outside linebackers group of Erik Walden, Dezman Moses and Frank Zombo mostly struggled while Matthews was sidelined. It's not a coincidence that Green Bay opted not to re-sign Walden or Zombo and then cut Moses at the end of this season's training camp.
This time around, the Matthews-less outside linebacker group turns to Nick Perry (who was on injured reserve at the time of Matthews' absence in 2012), Mike Neal (who was still a 300-plus pound defensive lineman at that point last season), undrafted Andy Mulumba and sixth-round pick Nate Palmer (who has yet to play a snap on defense in the NFL).
Given that Perry and Neal are coming off of what defensive coordinator Dom Capers described as each of their individual best games, there's reason for optimism from the Packers. Perry had two sacks and Neal had one against the Detroit Lions in Week 5.
But, even though he was just stating the obvious, coach Mike McCarthy called Matthews the team's best defensive player. Surviving without the best player on one side of the ball is not an easy task for any team.
Green Bay's record is currently 2-2, and if Matthews returns in four games -- as McCarthy approximated this week, the Packers' defense will have to do enough in the meantime to earn a couple victories with their star pass rusher unavailable.
2. Touchdowns needed from Green Bay's offense
For the Packers, the positive aspect of Mason Crosby making all five of his field-goal attempts in Week 5 was that their kicker's season-long slump of 2012 is officially a thing of the past. However, that also means that Green Bay's offense settled for five field goals and didn't convert any of those drives into touchdowns.
If the Packers continue scoring just one touchdown like they did against Detroit, many of those games won't result in wins like that one did.
Despite rushing the ball the best that it has in several years, Green Bay isn't capping drives with trips into the end zone with the same frequency. Last season, the Packers scored a touchdown 68.1 percent of the time that they got inside the 20 yard-line. That was second-best in the NFL. Though it's still early this season, Green Bay is down to a 56.3 percent touchdown rate in the red zone. That's tied for sixth in the NFC, which is above average, but it's going to take better numbers than that for the Packers to start piling up wins.
The problem for Green Bay trying to correct that problem in Week 6 is that Baltimore's defense has been fantastic inside the 20. Of the 12 drives that the Ravens have defended in the red zone this season, opponents have only scored four touchdowns, tying Baltimore for third-best in the NFL.
3. Kicking the Ravens' run game while it's down
Ray Rice has the reputation of an elite running back, but he sure isn't showing it this season. The Ravens' running game has been terrible, and Rice is playing a major role in those struggles.
As a team, Baltimore is ranked 27th in the NFL in rushing yards. Rice is averaging just 2.9 yards per carry and hasn't broken off a run for more than 20 yards yet in 57 attempts. Rice has also lost two fumbles.
The Ravens' offensive line isn't doing Rice any favors. According to ProFootballFocus.com, Baltimore is the league's second-worst run-blocking team this season. The Ravens will start Eugene Monroe -- whom they acquired last week in a trade -- at left tackle, but he hadn't been playing well with the Jacksonville Jaguars, so that's not necessarily an immediate upgrade.
The Packers' run defense is ranked fifth in the NFL. With big bodies like Ryan Pickett, B.J. Raji and Johnny Jolly upfront in the 'okie' 3-4 base defense, Green Bay has the personnel to continue being a strong run defense all season. But given how badly Baltimore has been running the ball, the Packers can't afford a slip-up in this game and let Rice begin to play like his old self.
4. Joe Flacco provides interception opportunities
After the first quarter of the season, Green Bay has just two interceptions. Though the Packers' secondary has been playing fairly well as of late (after their debacle in Week 1), the interceptions haven't been there. Fortunately for Green Bay, Flacco has been giving defenses plenty of chances to pick him off this season.
Flacco has already thrown eight interceptions. Five of those came in one game. Flacco's passer rating has him ranked 28th in the NFL. For a quarterback who signed a $120 million extension this offseason, Flacco isn't performing at a level worthy of that compensation.
Baltimore has a great wide receiver in Torrey Smith, but behind him, there isn't much. With Sam Shields on one side (perhaps matching with Smith), Tramon Williams switching between outside and the slot, and Davon House playing opposite Shields, the Packers will have to come up with a couple interceptions when Flacco inevitably throws a few balls up for grabs.
5. Road win No. 1 for the Packers?
Including late last season, Green Bay has lost four consecutive road games. That's a deviation from the Packers' typical success away from Lambeau Field in the years under McCarthy. But if Green Bay is going to win the NFC North again this season and have any shot at advancing to the Super Bowl, road wins are going to have to start coming in bunches.
Winning in Baltimore against the defending Super Bowl champions would certainly be a positive first step for the Packers in correcting their recent woes. With upcoming trips this season at Detroit, at Chicago, at Minnesota and at Dallas (the game in New York against the 0-6 Giants doesn't seem terribly challenging at the moment), Green Bay doesn't want to start their 2013 season with an 0-3 road record.