This is not a secret.

Indiana’s ailments on offense, which have prevented the Hoosiers from playing anywhere near a complete game in their first 4 outings this season, start and end with one unit: the offensive line. Despite having a largely veteran group, with returning starters at 4 of the 5 positions in addition to others who had gotten 1st-team snaps (and occasional starts) earlier in their careers, the Hoosiers are suffering massive failures in their offensive front.

And it’s becoming a killer. The issue will likely be the biggest obstacle the Hoosiers (3-1, 1-0 B1G) need to overcome if they are to get a critical victory Saturday night at Nebraska, where IU is a near-touchdown underdog, and in the next couple weeks, when it is likely to be an underdog to Michigan and Maryland despite playing those games in Bloomington.

The line’s shortcomings were never more apparent than Saturday, when Cincinnati chased IU quarterback Connor Bazelak down 5 times for sacks, one resulting in a fumble for a touchdown, another forcing an interception on an ensuing “and-long” down, and the others killing drives in the Bearcats’ 45-24 victory. And there were multiple other times that Bazelak was chased out of the pocket or nuked inside it, like on a 19-yard 1st-half touchdown pass to Josh Henderson when the IU quarterback hung in until the last second before being blown up as he delivered the football.

All told, Bazelak has been sacked 9 times this season, with 8 of those coming in the past 2 games.

And that says nothing of the line’s ability to open up running lanes for its backs. Indiana, which wants to rush the football to set up the pass, ranks 108th in the country (of 131) in rushing, averaging less than 115 yards per game. And its 3.4-yards-per-carry average is 106th.

So, what gives?

Indiana feels relatively comfortable with the left side of its line, where 5th-year senior Luke Haggard has started 15 straight games at left tackle and 4th-year junior Mike Katic has made 13 starts over the last 2 seasons at left guard, including all 4 games this year.

The questions are elsewhere.

At center, former Michigan transfer Zach Carpenter started Games 1 and 2, but an injury put him on the sideline, where his backup was saddled as well, leaving IU to start 3rd-string sophomore Caleb Murphy vs. Western Kentucky and Cincinnati. Junior Tim Weaver is in his first season as a full-time starter, doing so at right guard. And at right tackle, Indiana had to turn to senior backup Parker Hanna, who had started 7 games at left tackle for West Texas A&M last season, after veteran starter Matthew Bedford was lost due to an injury in Week 1.

The group hasn’t gelled.

“Didn’t play the way we have to up front, without question,” coach Tom Allen said during his weekly press conference Monday. “Some of the issues were collective. It wasn’t just them. But definitely they’re a part of it as well. It’s something that we’ve worked hard on. We’re going to have to look at adjusting maybe some of the five we play with, just try to find the best combination that we have to go with.

“That’s obviously on the table, part of our discussions, trying to get the best five guys on the field each and every time we play. The bottom line is they have to perform, be able to execute our run and throw game. That wasn’t done consistently on Saturday. High priority for us.”

Maybe Indiana tries to turn to its youth, rather than experience, especially on the right side. Allen has occasionally started to mix in sophomore Kahlil Benson at right guard and redshirt freshman Josh Sales at right tackle, hoping to find more consistent performances that can A) Keep Bazelak on his feet and B) Open up running lanes. But it’s a work in progress.

“The bottom line is,” Allen said, “whoever those five guys are on the field, they got to execute and give us a chance to be successful.”