Northwestern and Purdue kick off this Thursday, and it remains unclear who the starting quarterbacks will be for both teams. As regular readers of this site are well-aware, Northwestern signal-caller Clayton Thorson tore his ACL back in December, and might not be ready health-wise. If he’s cleared to play, he’ll start. If not, TJ Green will get the nod.

For Purdue, the situation is much more complicated. There are two contenders to start — Elijah Sindelar and David Blough. Both players have played extensively at Purdue: Blough started for the better part of 2015 and 2016 (and some last season), and Sindelar started the final four games of last season, playing well despite tearing his ACL against Northwestern.

Like Pat Fitzgerald, Purdue head coach Jeff Brohm has kept his cards close to the vest when it comes to the starting quarterback. Brohm has indicated that both quarterbacks could play, and he might ride the hot hand, but there’s a decent shot that both Blough and Sindelar get reps Thursday night. Here’s what the two quarterbacks bring to the table, and how they’ll pose different challenges to Northwestern’s defense.

Elijah Sindelar

Sindelar played in every game but one last season, finding his groove toward the end of the season. He threw for 376 yards against Northwestern on a cold night at Ryan Field last November, but it took him 60 attempts to get there with Purdue falling behind early.

At 6-foot-4 and 225 pounds, Sindelar has tremendous size, and a great arm to go with it. He can sling the ball all over the field, and he can really challenge the back end of a secondary, an area where Northwestern has uncertainty.

Take a look at this play, from last season’s game against Northwestern.

All videos courtesy of BTN2go.com

Sindelar smoothly fires a dart to the opposite side of the field, victimizing Alonzo Mayo in the process. Mayo took one step inside, and Sindelar made him pay. Against most quarterbacks, cheating inside will work when the ball gets snapped from the opposite hash. Not against Sindelar.

Check out this throw all the way across the field. It’s certainly a dangerous decision, but with a strong enough arm, it works. Sindelar also displays intelligent movement in the pocket to find an open pocket in the defense.

Jeff Brohm likes to get creative with his offense, and, in a primetime season-opener against a conference opponent, that should be no different. With how strong Sindelar’s arm is, Brohm has the ability to move the pocket around or experiement with deeper dropbacks, which you’ll see below.

When Sindelar is in the game, Brohm can go to a more pro-stlye, dropback-centric offense. Though he’s still relatively mobile, Sindelar isn’t so much of a threat to run, which limits the use of run-pass options (RPOs), which have given NU and Mike Hankwitz fits (no pun intended) in recent seasons. A more prototypical play-action is still a big part of the playbook with Sindelar, though, which was effective last season against NU.

On the following clip, the play fake freezes safety Kyle Queiro (No. 21) in the middle of the field, and Marcus McShepard is one too slow. Touchdown.

You’ll see a similar sequence here.

Breaking in new starting safeties, Northwestern will need to neutralize Sindelar on the play-action Thursday.

David Blough

A Texas native, Blough could’ve transferred elsewhere and played immediately, but chose to stay at Purdue and compete for the starting job. Blough is impressive off the field, but has been up-and-down on it. He played on some pretty bad Purdue teams in his first two seasons (in 2015 and 2016), where he was often running for his life and attempting tons of passes while playing from behind. He also had to take more chances, which led to a lot of interceptions (four of which came in two games against Northwestern).

When it comes to how Blough differs from the Sindelar, the most obvious distinction is size, which manifests itself in running ability. Blough stands at 6-foot-1, and brings a running component to his game that Sindelar doesn’t have.

On the following play, you’ll see Blough drift outside the pocket, before bailing on the pass and taking off for a first down.

In turn, the pass-rush needs to be slightly less aggressive with Blough on the field, because he’s more able to burn you on the outsides if the defensive ends lose contain.

Similarly, RPOs are a much bigger part of the offense when Blough plays. Now, that doesn’t mean Blough runs that much (he doesn’t), but the increased threat of him keeping the ball on the option freezes the defense enough to create space for a quick-hitting passing game.

Blough is also quicker and more elusive in the pocket than Sindelar, and he’s good at resetting his feet quickly to deliver accurate passes, even when the rush is bearing down on him.

Sindelar may have the better arm, but Blough isn’t deficient, either. In the following clip, he stands in the pocket and tosses a beautiful ball to the outside (though the receiver drops it).

Conclusions

Sindelar and Blough both have talent, but neither has been super consistent thus far in their careers. Sindelar is the younger player and the newer starter, so he probably has more room to grow, but both players are capable of beating Northwestern with some help. Because their styles are a bit different, Northwestern’s defense will have to make adjustments depending on which player is on the field.

Without being certain, it seems like Brohm will play both quarterbacks, unless one comes out and dominates early. Northwestern has proven that a two-quarterback system can work, but there are often issues with finding a rhythm. Season openers are strange in that teams are trying to get a feel not only for their opponents but for themselves, so it would make sense for Brohm to give each of his quarterbacks some time early. He’ll probably even run some Wildcat too, which he used against Northwestern last season.

In an opener that figures to be close, and that is unquestionably important for both teams, the uncertainties in both quarterback rooms add intriguing twists to an already compelling matchup.