Nam Y. Huh/Associated Press

On Thursday night, the Jacksonville Jaguars visit the Chicago Bears as both teams play their second game of the preseason—and they'll do so in front of a national audience, as it's the lone NFL game on the schedule.

While the second game of the preseason pales in comparison to the all-important third contest (which functions as a dress rehearsal for the season opener), it's still of vital import. There are players being worked into new systems, position battles to be decided and much more.

Let's examine what to watch heading into Jaguars/Bears on Thursday night, the preseason Week 2 opener.

Blake Bortles Seeks to Impress Again

Since they selected quarterback Blake Bortles with the third overall pick in this past May's draft, Jaguars coach Gus Bradley and general manager David Caldwell have publicly stated the plan is for Bortles to "redshirt" his rookie campaign and see the field in 2015.

But if Bortles continues to author performances like his preseason debut last week against the Tampa Bay Buccaneers, he's going to prove difficult to remove from the lineup.

Bortles was spectacular in his first NFL action, completing 7 of 11 passes for 117 yards. His arm strength was evident on several throws, and he moved well in the pocket, evoking memories of a young Ben Roethlisberger.

By comparison, the Jaguars' incumbent starter, Chad Henne, completed only 4 of 7 passes for 30 yards against Tampa Bay. While Henne is still the clear favorite to start in Week 1, Bortles has undeniably gained some ground and impressed teammates and coaches alike.

After the game, Bradley told Fred Goodall of The Associated Press (h/t ABCNews.com), "I thought (Bortles) did a nice job, showed some good poise. We felt like we could protect him. Just the poise factor, we wanted to see that in him, and he did a nice job."

Earlier this week, Bradley announced, per Michael DiRocco of ESPN.com, that Henne would play the entire first half against Chicago, and Bortles would play the full second half. That jibes with the Jaguars' desire to have Henne start the season and (hopefully) perform well enough to remain in the lineup, but it's also clear Bortles is going to get a long look from the coaching staff.

Bortles' continued development is the biggest story to emanate from this contest, and he'll have 30 minutes to showcase it.

Jared Allen Set to Make Bears Debut

In 2013, Chicago's defense was dreadful, allowing a preposterous 5.3 yards per carry.

Heading into the offseason, general manager Phil Emery's directive was clear: Fix a broken defense that would be capable of matching the elite level of the team's offense.

Emery consummated a rash of transactions, both via free agency and the draft, to achieve that goal, but none was larger than the signing of defensive end Jared Allen, the owner of 128.5 career sacks.

Charles Rex Arbogast/Associated Press

The 32-year-old Allen showed he still has gas left in the tank with an 11.5 sack performance in 2013 for the Minnesota Vikings. Given that the Bears could only manage 31 sacks as a team last year (tied with Jacksonville for worst in the league), Allen's projected impact will be critical.

Allen missed Chicago's preseason opener, a 34-28 victory over the Philadelphia Eagles, because his wife gave birth to a baby girl. That means Allen's first action as a Bear comes on Thursday night against the Jaguars.

Bears fans will surely be watching closely, as a dominant Allen would do wonders for the Bears' postseason hopes.

Toby Gerhart Will See the Field

Earlier this offseason, the Jaguars signed former Vikings running back Toby Gerhart to a three-year, $10.5 million contract to be the bell cow of their offense.

Gerhart, who has averaged 4.7 yards per carry over four NFL seasons as Adrian Peterson's backup, will see his first action as a Jaguar on Thursday night. He missed the opener against Tampa Bay with a hip flexor injury.

Last week against the Buccaneers, the Jaguars had issues rushing the football, toting the rock 33 times for only 91 yards, good (or bad) enough for an average of 2.8 yards per carry. And if you subtract Denard Robinson's 23-yard touchdown jaunt, the numbers look even worse (32 carries for 69 yards).

Gerthart will be leaned upon heavily this season in Duval, and his quest to establish himself as a lead back begins in earnest Thursday night.

Count Bleacher Report's Mike Freeman as a Gerhart believer.

Who Will Emerge as the Backup to Bears QB Jay Cutler?

Jay Cutler is the clear-cut starting quarterback of the Chicago Bears. That much we know for certain.

What's more nebulous is the situation behind Cutler, as three different passers seek to be installed as his primary backup.

Jimmy Clausen, Jordan Palmer and rookie David Fales are all competing for the job, and after an excellent performance in the team's preseason opener against the Eagles, Clausen appears to be the favorite.

Clausen completed 7 of 13 passes for 150 yards and two touchdown passes, while Palmer went 8 of 11 for 104 yards, one touchdown pass and one interception. Fales came in last and completed 5 of 7 passes for 68 yards and an interception.

Earlier this week, Bears coach Marc Trestman announced that Clausen be the No. 2 quarterback against Jacksonville, saying, per Andrew Seligman of The Associated Press: “Right now, we’re going to have Jimmy relieve Jay. He’ll have the shot whenever Jay comes out of the game, whenever that is. But both of them (Clausen and Palmer) will play."

On the surface, Clausen and Palmer don't inspire much confidence. Neither has thrown a regular-season pass since 2010, and it's tough to imagine either playing as well as Josh McCown did last year if Cutler succumbs to injury.

But right now, thanks to their sterling play in the preseason opener, the vibes are positive.

After Thursday night's contest, we'll have a better idea of who will enter the season as Cutler's primary backup.

And given Cutler's injury propensity (he hasn't played a full 16-game slate since 2009), it's vital that the backup be ready to play and lead the offense if needed.

Marqise Lee Needs to Step Up

Two of the Jaguars' projected top three receivers, Cecil Shorts and Allen Robinson, will not play against the Bears, as both continue to work back from hamstring injuries.

So, for the second consecutive week, rookie receiver Marqise Lee will serve as the primary target in the Jaguars' passing attack. And the team is undoubtedly hoping for a better effort than he displayed last week against the Buccaneers, when Lee played 16 snaps and caught zero passes.

Bradley was frustrated with Lee in the game's aftermath, telling Ryan O'Halloran of The Florida Times-Union, "It wasn’t exactly where we need (Lee) to be."

The Jaguars are desperate for downfield playmakers and need Lee to step up. He'll get another chance to excite on Thursday night in Chicago.

Can Zach Miller Continue to Make an Impact?

Former Jaguars tight end Zach Miller (not to be confused with the tight end Zach Miller who plays for the Seattle Seahawks) hasn't caught a regular-season pass since 2011, but he sparkled in his Bears preseason debut, hauling in six passes for 68 yards and two touchdown catches.

Nam Y. Huh/Associated Press

While Miller's presence will be mitigated by the return of starting tight end Martellus Bennett, he still looms as a player to watch.

The Bears' projected third receiver, Marquess Wilson, is on the shelf with a broken collarbone, leading to speculation that the Bears could field more two-tight end sets, as written here by Brad Biggs of the Chicago Tribune.



If Miller continues to shine, he could carve out regular-season playing time alongside Bennett and receivers Brandon Marshall and Alshon Jeffery—at least until Wilson returns from injury.