They have to protect Blaine Gabbert.
They have to pressure Jay Cutler.
It may seem ridiculous to boil a complex NFL matchup down to just two areas, but no matter how you parse the data and the film, the matchup will be decided by the Jaguars' ability to do the two things they do worst.
Jacksonville is 31st in the NFL at rushing the passer with just two sacks on the year. Only five teams have allowed more sacks than the Jaguars' 12 too.
One of them is the Bears.
There won't be five points in this game plan. The Jaguars have to do two things and do them well.
Obviously, Gabbert's sack issues have been a problem his entire career. His sack rate is actually worse in 2012, though it's obviously not entirely his fault.
Jacksonville has had trouble at every line spot, and even Eugene Monroe, who has played well overall, was outmatched on plays against the Bengals.
The Bears are going to do do their best to come after Gabbert with their front four. While they will run some exotic stunts from time to time, Chicago wants to get the quarterback on the ground without the blitz.
With rushers like Julius Peppers and Israel Idonije, the Bears believe they can beat the Jags' linemen.
Against Cincinnati, Jacksonville had assignment breakdowns caused by the blitz. Against the Bears, it will be stunts. Chicago will bring all four down linemen from any possible angle in an effort to confuse the blockers.
Obviously, it's not rational to expect the Jaguars to miraculously improve talent-wise in a week. However, with good film work, they might be able to be better prepared for Chicago than they were the Bengals.
I'm going to take a moment to review tape of all the Jaguars' sacks this year. Please wait a moment.
There. That didn't take long.
Jacksonville had two sacks of Christian Ponder in Week 1, but has gone three weeks without getting to the opposing quarterback.
Both of the sacks against the Vikings were the result of good coverage downfield rather than outstanding play by the defensive line.
Jacksonville has invested high picks in their defenders. Be it Tyson Alualu, Andre Branch or Terrance Knighton, the Jaguars have what ought to be good talent.
Branch especially has been a disaster, routinely making no impact at all despite plenty of playing time.
Alualu was already in a make or break year, and despite Mike Mularkey's assertions, he certainly looks more broke than made.
The good news for the Jags against Chicago is that Jay Cutler loves to hold the ball too long. If Derek Cox can manage to matchup against Brandon Marshall for most of the game, it's conceivable the Jaguars could generate some long hold times for Cutler.
If the secondary can give the line the extra time they need to land, they can harass Cutler into making the kind of mistakes that plagued him against Green Bay.
Any time a team is asked to do things it doesn't do well, the outlook is obviously bleak.
The Bears are playing extremely well on defense and will be looking to get Gabbert on the ground. If they succeed in picking up four or more sacks, there's almost no scenario in which the Jaguars win the contest.
If Gabbert gets time to throw, he'll have to prove he can beat a good secondary. It would be nice if he got the chance to succeed or fail on his own without being held down by the line.
The other side of the ball offers little additional comfort. Given their struggles to get pressure, the obvious fear is that Jay Cutler will pick apart the back end of the Jacksonville defense.
It's hard to see this game turning out any differently than the Jaguars' other home games did.