Coming off a sub-par season in which Purdue lost four in a row — a streak it carries into 2021 — Jeff Brohm’s Boilermakers have a lot of questions.

Defensively, Purdue has an entirely new staff, and on offense, it still hasn’t solved the QB quandary. Those questions and more below.

1. Who wins the QB battle?

Give Aidan O’Connell a slight edge entering training camp, ahead of fellow experienced returnee Jack Plummer. Why? O’Connell won the job for Game 1 last season, and probably wouldn’t have given it up had it not been for a foot injury. That he led Purdue to a 2-1 record in the first three games helps as well.

The 6-foot-3, 200-pounder is a big, strong-armed pocket quarterback who can drive the ball down the field to veteran wideouts David Bell and Milton Wright. And he’s shown an incredible knack for keeping Purdue in games, then driving the Boilermakers to a win late.

But the job won’t be given. Plummer, who started the final three games last season, is a better athlete who adds an element of elusiveness to Purdue’s backfield, and it’s not as if his arm is below average.

Brohm has indicated Purdue will name a starter internally soon after camp starts; when the public knows, however, isn’t as clear.

2. On an experienced line, who starts at left tackle?

Had he not injured his knee last season, the most likely candidate to replace departed 4-year starter Grant Hermanns might be sophomore Cam Craig. But Craig, who was a left guard last season before the injury, might be eased back in on the right side.

So perhaps Greg Long, last season’s starter at right tackle, slides to the blind side. It seems the likely answer. Long, a former JC transfer, exceeded expectations in his first season as a Boilermaker, mostly because he was finally healthy after years of battling injuries.

3. Does the defensive staff overhaul pay dividends?

Purdue better hope so. The Bob Diaco-led defense last season didn’t work, as it was completely against type for Purdue. The bend-but-don’t-break style didn’t mesh with Brohm’s desire to be aggressive on offense. And the 3-4 front wasn’t a fit for the Boilermakers’ personnel, either.

So Brohm brought in Brad Lambert to call the plays during the offseason and then added three more assistants, a complete overhaul that he hopes will lead to results.

It should. Purdue wants to be more aggressive in its front, an approach that could lead to more plays, both positive ones and negative. But if the Boilermakers can gain an extra possession or two per game, then they might be able to win in shootout fashion. And a win is a win, right?

4. Which defensive transfer makes the biggest impact?

There are plenty of options, with Purdue bringing in more than a half dozen from the portal during the last several months.

But linebacker OC Brothers, who had started his career at Auburn, seems like a sure-fire starter. That he was around in the spring and could learn Lambert’s defensive system also gives him a leg up.

5. Can Purdue punt successfully?

Yes.

Probably?

It was an offseason priority to upgrade Purdue’s punting, after it used three punters last season, none with much success. The Boilermakers are fortunate that it didn’t cost them 1 of their 2 victories, after a second-half shank parade vs. Illinois almost helped the Illini rally in Week 2.

Brohm turned to the Southern Hemisphere to bring in a new option, with Jack Ansell signing on to bring some consistency to the position. Ansell follows in a line of Australians to the Big Ten, like IU’s Haydon Whitehead, who was one of the conference’s best punters a year ago.

Purdue is looking for similar results.

6. Is Yanni Karlaftis a Day 1 starter?

If Karlaftis stays healthy, he certainly could be.

But the younger Karlaftis, a 4-star linebacker from nearby West Lafayette High School, missed most of his senior year and his first spring at Purdue with a lingering hamstring injury. Purdue is likely to work him back in slowly, as to try to discourage a relapse.

But it’s all hands on deck for Lambert, the new linebackers coach. Junior Jaylan Alexander and senior DaMarcus Mitchell are two of the few returnees with experience, and Brothers will fill a role, too.

But Karlaftis will be right there, as well.

7. Does Purdue have a pass rush?

It didn’t last season, with only 5 sacks in 6 games, the worst rate in the Big Ten.

End George Karlaftis led the Boilermakers with 1.5, although he played in only 3 games due to an injury and contracting COVID. And when he was playing, he was mis-cast in Diaco’s defense.

Now, with new defensive line coach Mark Hagen — the assistant and player have quickly bonded — the Boilermakers should be more active in their front. But there’s not a lot of experience in that group, particularly with senior tackle Anthony Watts set to miss at least the start of the season.

Purdue will have to figure out who starts opposite George Karlaftis. Maybe it’s Mitchell, who showed promise in his first season at Purdue in ’20. He can play linebacker or end.

Regardless of the personnel, Purdue can’t sit back this season and it won’t.

8. Will the Boilermakers run the football?

Purdue was dead last in the Big Ten in rushing last season, averaging only 81.5 yards per game. And it has the same personnel — starter Zander Horvath and backup King Doerue — back this season, with little other depth.

It’s never going to be Priority No. 1 for a Brohm offense, but it has to at least provide a bit of balance to the pass-first (and second) approach. An improving offensive line will help, as will better health for Doerue, who had only 64 yards rushing last season after being slow out of the gate due to injury. And Horvath is a solid workhorse back — 442 yards last season — capable of putting up big numbers because of his strength and sneaky speed.

Those are the positives. But outside of Horvath and Doerue, Purdue has no other experience, and frankly it doesn’t have a wealth of depth of any sort after its scouring of the transfer portal during the offseason didn’t pan out. So Purdue will try to make it through the season with only the two backs unless a third surprisingly emerges.

9. Is O-line depth suddenly an issue?

Backup center Sam Garvin, who has been a starter the last two seasons, is the latest to suffer an injury on the offensive line, a rash of issues that it sapping the line of its depth.

This offseason, Purdue has lost Kyle Jornigan, Will Bramel, Mark Stickford and Garvin to injuries — the first three are no longer on the team — all of whom have starting experience, although were slated to likely be reserves this season.

It hurts.

But Purdue feels good about the first unit, with Long, left guard Spencer Holstege, center Gus Hartwig, right guard Tyler Witt, a graduate transfer, and Craig (or perhaps Eric Miller early in the season) at right tackle.

Veteran D.J. Washington can slide around on the inside and Miller could develop into a swing tackle. But now Purdue’s only an injury or two away from having to throw in a player before he’s ready.

10. Outside of QB, what’s the biggest position competition?

Junior Cory Trice will be one starting cornerback.

But who is the other?

Senior Dedrick Mackey has starting experience, and while he’s been okay in coverage, his run support has shown room for improvement. Purdue worked to add depth — or more options — during the offseason, adding transfers Jamari Brown from Kentucky and CJ McWilliams from Florida, but the latter’s season is in doubt due to a non-football-related injury.

Purdue has seemingly had questions at cornerback for years now, one that new assistant James Adams wants to remedy as quickly as possible.