Pittsburgh led the nation in sacks last season behind a line led by Big East co-defensive players of the year Greg Romeus and Mick Williams.
With Williams graduated and Romeus out until the final third of the season following back surgery, Pittsburgh will try to prove it has a few more linemen in the pipeline.
The Panthers' matchup tonight with Miami is a crossroads game of sorts for both teams; each was in the preseason top 15 but each already has lost once, Pitt at Utah and Miami at Ohio State. It also will be a matchup of teams with question marks along both lines.
But Pitt has the biggest question to answer: Who is going to step up to replace Romeus, a preseason All-American candidate who is the Panthers' best defender?
"We plan on rolling people out and letting our depth show," Pittsburgh defensive line coach Greg Gattuso said.
While Pitt's defensive line depth showed in its last game against FCS powerhouse New Hampshire, the prime-time game against Miami will provide a much bigger challenge.
Junior Brandon Lindsey started in place of Romeus, recording two sacks. He will remain a starter against Miami. In a reserve role, Lindsey had three sacks in consecutive routs of USF and Syracuse last season.
Pitt will rely on more than Lindsey, though. Freshman T.J. Clemmings, a four-star recruit out of Paterson, N.J., will bypass a redshirt year to back up Lindsey. Senior Nate Nix also will see playing time.
"You don't replace the co-Big East defensive player of the year and potential first-round pick overnight, but Brandon has had a good week of practice and he'll be ready to go," Pittsburgh coach Dave Wannstedt said.
Lindsey may be the focal point since he's stepping in at Romeus' position, but the Panthers have one starter remaining from last season's line, end Jabaal Sheard. Gattuso can't ask him to make up for all the missing production, but he can push him to be the leader of the group. Sheard had five sacks and 12 quarterback hurries last season.
Sheard is from Hollywood Hills, Fla., about an hour north of Miami's campus, and grew up a Hurricanes fan. But he was not a recruiting priority for UM coaches.
"Things didn't work out," he told the Pittsburgh Tribune-Review. "There's a little grief inside, but we will take it out Thursday and be done with it."
Tackles Myles Caragein and Chas Alecxih are upperclassmen, but they're also in their first seasons as starters. Both struggled against Utah, but Gattuso said he expects those two to rebound in their second start in a high-profile game.
Sheard's impact, meanwhile, must be felt in the huddle and on the sideline as well as after the snap.
"The one area where Jabaal Sheard must step up -- and will -- is leadership," Gattuso said. "He is now the senior on the front four. A guy like Myles Caragein needs to up his leadership ability, too. Guys will have to pick up things like that."
The injury to Romeus couldn't come at a more critical juncture for Pittsburgh. The Panthers were the preseason favorite in the Big East, but they are in danger of falling to 0-2 this season against FBS teams. The key to avoiding that kind of start is pressuring Miami quarterback Jacory Harris into mistakes.
Harris has shown a propensity for making bad decisions. He threw 17 interceptions last season after tossing seven in part-time duty as a freshman in 2008. Harris also threw four picks against Ohio State, but Miami coach Randy Shannon said only one of those was his fault.
"He was sharp in that game," Shannon said. "We have to get guys catching the football. Two of his interceptions basically went into his receivers' hands and bounced to the other guys."
Pitt's defensive scheme requires the line to put most of the pressure on the quarterback without much support from blitzing linebackers. Some potential good news for the Panthers is that Miami starting offensive tackle Joel Figueroa may miss the game with a shoulder injury; if he can't go, redshirt freshman Jermaine Johnson would make his first college start.
The Panthers averaged 3.6 sacks per game last season primarily because of the play of Romeus and Williams. Now, Pitt is without both.
"If Jacory Harris sits back there with time to throw, we're going to have a long night," Gattuso said. "We've got to get to the quarterback in passing situations, and we're not going to get a lot of help. We're not going to have four linebackers blitzing. We're not like that.
"We'll mix our pressures, but we need our front four to stand tall."
Miami, meanwhile, could be without as many as three defensive linemen. Backup tackle Curtis Porter is out with a knee injury, while backup tackle Luther Robinson (lower leg) and starting end Marcus Robinson (ankle) are considered questionable. End Allen Bailey could slide inside and play some tackle; his pass-rushing ability could pay off on the inside, considering that Pitt's offensive interior has some issues.