Bengals defensive line coach Jay Hayes is vying for an eight-man rotation. It already looks like he has seven with the five starters (consider all-everything end-tackle Wallace Gilberry a No. 1) backed up by tackle Brandon Thompson and right end Will Clarke.

That's if Clarke keeps up his eye-catching play from this spring's work on the field in the voluntary practices and they expect him to be better when they get the pads on.

So if those are the top seven defensive linemen, who is No. 8 in the rotation and who is No. 9 on the roster?  No. 8 could be a tackle in veterans Pat Sims or Devon Still or a rookie in fourth-rounder Marcus Hardiston, or an end in third-year man Margus Hunt.

Hunt, a second-rounder in 2013, hasn't practiced all spring and published reports said he revealed Tuesday that he suffered a lower muscle injury in his back while lifting in April. If he's not ready for the first day of training camp, he believes he'll be back in time to play at least some of the pre-season games.

Still, who played 12 games last season in a backup role before being deactivated for the final three of the year, hasn't practiced this spring as he deals with the health issues of five-year-old daughter Leah. But he's on the mind of his teammates and coaches.

"Still, from what I've heard, is in really, really good shape," Hayes said. "I've only seen him on Instagram and stuff like that, but I saw him bench 405 (pounds) five times (Monday). That was pretty impressive."

FISHER CATCHES ON: Offensive lineman Jake Fisher showed why the Bengals grabbed him in the second round during Tuesday's voluntary practice. It wasn't so much his abilities, which the Bengals had targeted in the first round. But there are also his intangibles and personality, which they had off the charts after his pre-draft visit.

Despite struggling at times working through a huge learning curve with the Bengals system, Fisher has kept his head up and drew raves when he caught two balls as the extra tight end, including a nifty spin move on nine-year safety Reggie Nelson.

"He's a guy that's got a lot of ability," said left tackle Andrew Whitworth. "He's just got to continue to focus in and learn and adapt to the game. He's going to be a guy that's got a skill set that you can use. He could be that big tight end for us. It's definitely a weapon."

Fisher has a tougher charge than Whitworth did after he arrived in the second round in 2006 in the sense that Whitworth came out of LSU's pro offense. Offensive line coach Paul Alexander says Fisher is learning "a different sport," when it comes to the technique the Bengals employ compared to Oregon's fast-break scheme.

"All of our guys have had to take time to make the transition. Whit. Andre (Smith), Levi (Jones), Stacy (Andrews), Willie (Anderson)" Alexander said. "It's like starting over. It's been true of every guy we've had. It didn't take too long. We see him the in the normal progression. If anything, he's  ahead. He's playing four spots…He's getting there and he's going to be fine."

It looked like Fisher played three positions alone on Tuesday, an Alexander no-no with a rookie until Fisher. With Whitworth alternating days befitting a 10-year vet, Fisher got some time at both tackles and left guard. Whitworth realizes Fisher's challenge because of the importance of technique. He says it's the biggest difference between pros and college.

"He's got a lot to learn. He'll learn it as he goes," Whitworth said. "Just learning how good you have to be technically. I think that's what he's learning now. It's not like in college when you can get away with your skill set. At this level, if your technique is not great every play, there's a chance you're getting beat. You have to play technically  sound all the time rather than one (snap) every so and so."

How about this? The only two guys on the field Tuesday that caught a TD pass from Carson Palmer were Whitworth and spring coach T.J. Houshmandzadeh. Whitworth's one career catch came from one yard out from Palmer, the Bengals' only score in a 23-7 loss in Pittsburgh in 2010.

So Whitworth had some fun with the two catches by Fisher.

"Unfortunately when  you get to blocking too well, that's what they want you to do," Whitworth joked. "I told them I'm going to start blocking worse. But no, that will be a good thing for us, to have him come off for us and not necessarily be a threat, but be an option. It gives you the ability to have six O-linemen on the field  and still have the ability to throw the football as well."

MORE HOUSH:  Houshmandzadeh, working here this week and next week in the Bill Walsh Minority Fellowship program for coaches, was all smiles when he heard that wide receiver Marvin Jones had been listening.

"He's talking about knowing the defense. Know what the linebackers have to  do, the defensive linemen have to do," Jones said. "It makes your job easier  because you'll know when you get the ball or when you should get the ball based on what is happening. He's been great."

With his signature pony tail and years of clutch catches, Houshmandzadeh is one of the more recognizable NFL players from the previous decade, so he was well known in the locker room when he showed up Monday. Jones is especially familiar with No. 84 because in his last season at California former Bengals quarterback Akili Smith was an assistant coach for the Golden Bears and supplied Bengals' training camp tape from the days of Palmer, Houshmandzadeh, and Chad Johnson.  

"My eyes were glued to what he did. The way he'd get open, how crafty he was," Jones said. "His knowledge. I watched a lot of that…A guy like that who talks about the situations he was in and what he's seen us in, you want to be on his hip."

When Houshmandzadeh spoke to the room, seventh-round pick Mario Alford, wide receiver West  Virginia, was particularly attentive since Houshmandzadeh became the club's third all-time leading receiver after being taken in the seventh round in 2001. He told the receivers that more coaching eyes are going to be on the other guys rather than on starts like four-time Pro Bowler A.J. Green.

But Green said he has already learned from Houshmandzadeh, but wouldn't reveal what.

"He knows his stuff," Green said. "It's great to have a veteran who has been through it all to talk to the young guys."

Like what? Green was asked.

"Can't say,' he said.

Which is maybe what he learned.