I realize Pitt is re-transitioning to a 4-3 defense, from the 3-4, but given that it was only one season. And most of the players were already schooled in the 4-3 principles, I’m not going to be buying too many excuses for struggling based on that move.

On the other hand, the linebackers themselves may be a big concern. Todd Thomas appears to be slower coming back from his ACL injury than hoped. Shane Gordon is out, Ejuan Price is coming back slowly from a spring injury, and several others appear to be dinged up at the moment. Heck, moving to a 4-3 may have been necessary based on the depth chart.

With Thomas out, and linebacker Shane Gordon “day to day,” fifth-year seniors Manny Williams and Joe Trebitz have filled those roles. Wednesday, redshirt freshman Jason Frimpong found himself practicing with the first-team linebackers after Eric Williams went down with an injury.

Trebitz played in 12 games last year, but registered just five tackles. Manny Williams didn’t see meaningful playing time.

Now, Chryst said, is the chance for those guys to prove they deserve playing time once the presumed starters return.

“We’ll find out [about our depth] as you go through in practice,” Chryst said. “Because of the guys that aren’t practicing, other guys have opportunities and we’ll see what they do with that opportunity.”

Lots of questions about how the linebackers will turn out, since there isn’t a lot of experience.

Hindsight is always 50-50* but given the way last season went, I wish Todd Thomas had not waited until the end of the season to have the ACL surgery.

Thomas, a graduate of Beaver Falls, tore the ACL in his left knee last season while making a fourth-down stop of South Florida quarterback B.J. Daniels. Immediately, the knee felt tight, but he jogged on the sideline, and the feeling went away. Over the next few days, there was minimal swelling, and he was able to maintain strength in the knee, which suffered little collateral damage.

Heartened, Thomas delayed surgery four months to play most of the rest of the season. He missed the next two games — losses to Rutgers and Utah — but played five of the final six, recording seven tackles and a 39-yard interception return against Cincinnati.

Payment came due in January, when Thomas had surgery and started down a long, painful road to recovery.

Now we have to hope he can recover in time, and get his conditioning up to snuff.

Manny Williams is one of the players who it is hoped has things click in his final opportunity.

I think Manny has taken ownership,” Pitt coach Paul Chryst said of Williams Saturday after another productive practice by the linebacker.

“We talk about our seniors playing the best football, and I think Manny’s approach is exactly what you want. He’s into it, he’s enjoying playing when he goes out there and he’s had a couple back-to-back days where he’s had success.

“I think that gives you confidence, and it gives guys around you confidence. He’s been fun to watch the last couple of days.”

Williams doesn’t know why his performance in this camp is different from his first three years at Pitt, but he said he can’t change the past. Instead, he is focused on finishing his career on a high note.

It is very possible that the linebacking situation will remain as tenuous as the O-line. Unlike the O-line, the linebackers have some help in the form of the safeties.

Senior Jarred Holley (5 feet 10) of Easton, Pa., one of only three returning Big East all-conference players on the team, and 6-0 junior Jason Hendricks of Brooklyn, N.Y., have worked as a tandem, but they have had to alternate first-team reps with senior Andrew Taglianetti of Central Catholic and sophomore Ray Vinopal of Youngstown, Ohio.

House said there has been no real separation between the safeties but expects it to get sorted out now that the Panthers will be in full pads for the duration of camp.

Taglianetti, who is also an exceptional special teams player and likely will work as the nickel back on passing downs, said that the competition is good for all of the players because it is pushing them all to a higher level.

“We have four safeties who can play, we have four corners who can play right now,” Taglianetti said. “I mean, the younger guys, a lot of them can play as well, but to have four game-ready guys at both positions is an asset. And there is a lot the coaches can do with it because he can put combinations of guys with speed, guys who can cover, guys who can make plays — there is so much they can do.

“And for all of us, we know we need to bring our best to every practice because there are other guys ready to step in and you can see how intense the competition is becoming. That makes us all better and it makes the team better.”

The safeties in defensive coordinator Dave Huxtable’s unit will be asked to fill the hole and provide run support and even blitz far more often than they had in the past. That means the corners often will be left in man coverage.

In recent years, the corners have played a lot of zone so there will be an adjustment for them to being manned up.

We might see Pitt in nickel packages this year, even in non-passing downs if the linebackers don’t get healthy. The fact that Huxtable’s defenses bring the safeties up is a nice coincidence. I think there wouldn’t be much choice for any DC with the present state of Pitt’s linebacking depth.

So, so many questions.

*We know that Walt Harris said it, but apparently Steve Spurrier is also credited with saying that during his Redskins stint. As is Pat Dye.