PITTSBURGH The Carolina Panthers knew Jeff Otah wasn't going to play Thursday night, but the question is quickly becoming how many more he will miss?

The starting right tackle, who's been out since having an arthroscopic procedure on his left knee early in training camp, is not expected to be ready for the regular-season opener and perhaps the week after that, according to a source with knowledge of the situation.

The source said Otah had a setback during his rehab, which adjusted his return date.

When Otah had the knee scope on Aug. 4, team officials said they were hopeful he'd be ready for the Sept. 12 trip to play the New York Giants.

"I think it was a good move and something he'll recover from pretty quickly," Panthers coach John Fox said in August.

Otah still hasn't been activated from the physically unable to perform list, or practiced this year. He stayed behind in Charlotte with the rest of the injured players.

He went on injured reserve last season after suffering a torn meniscus in his left knee, missing the last three games. He also missed four games in 2008 with ankle problems, raising questions as to how he'll hold up. At 6-foot-6 and 335 pounds, Otah is one of the more dominant run-blockers in the league when healthy, but the lower-body injuries have to be a concern.

In his absence, the Panthers will continue to start Geoff Schwartz at right tackle. He played well in relief of Otah the last three games last season, when the Panthers averaged 183.0 rushing yards per game. But it does create some interesting decisions for the Panthers in terms of picking their 53-man roster this weekend, and could buy backup tackle Rob Petitti some time.

If they thought Otah was going to miss extended time, they could place him on reserve-physically unable to perform, which would hold him out at least six weeks. However, they've given no indication the problem is serious enough to warrant that.

CLAUSEN SITS: After some discussion of giving starting quarterback Matt Moore a few series, the Panthers went straight to backups Hunter Cantwell and Tony Pike.

Rookie backup quarterback Jimmy Clausen didn't play at all.

That probably wouldn't raise a red flag - the Panthers are trying to decide whether to keep Cantwell or Pike as their third - but for Clausen's recent admission that the right big toe he had surgery on in January was still bothering him. Clausen said he didn't expect to be 100 percent this season. His toughness can't be called into question, as he played his final season at Notre Dame with two torn toe ligaments.

His agent, Gary Wichard, said Thursday that Clausen was working through some "shoe issues," but said the quarterback was fine and the toe problem wasn't a concern.

TAKE THE NIGHT OFF: The Panthers left nine players back in Charlotte, but they could have saved a lot more on airfare and hotel rooms.

Wide receiver Steve Smith and running back Jonathan Stewart were expected to be held out, but the Panthers elected to sit both starting lineups.

Cantwell opened the game behind the second offensive line, with running back Mike Goodson and wide receivers Dwayne Jarrett and Brandon LaFell. The defense was a hodge-podge, with potential starters Louis Leonard and Derek Landri at defensive tackle, but the rest of the regulars tucked safely away. They also used Ed Johnson and Tank Tyler liberally, as they're trying to decide which of those four to start.

Those who stayed behind were defensive end Tyler Brayton, cornerbacks Richard Marshall, Captain Munnerlyn and C.J. Wilson, safety Aaron Francisco, running back Tyrell Sutton, wide receiver Trent Guy, guard C.J. Davis and Otah.

OBSERVATIONS

Yep, that's right, they charged full fare for this one. The crowd was as spotty at Heinz Field as it has been in other locations in the preseason, even back home at Bank of America Stadium.

While the Panthers starters were held out, the Steelers let theirs play two series each.

Panthers defensive end Greg Hardy and Landri got good pressure against the Steelers starters, a good sign for a side that has exceeded expectations all preseason. The Steelers starters managed just a field goal in two drives against the backups.

They're doing everything they can to find a role for rookie wide receiver David Gettis.

He hasn't done enough as a pass-catcher to merit inclusion on the roster in front of some others, but he's big and he has track speed, so they're loathe to cut him.

He looked good on a 30-yard kickoff return, but with so many young players competing for so few jobs, it's unclear if they're going to find a spot for him, or hope he clears waivers so they can sign him to the practice squad.

Wide receiver Charly Martin has only started catching passes from quarterbacks in the past week, but he's proving his worth late in camp.

Sidelined early by a broken left middle finger (thus unable to catch, kind of a requisite for receivers), Martin pressed trainers to let him do special teams work.

It's a good thing he did. He came up with two tackles on punts in the first half, evidence that he could well slip into the roster spot which was formerly held by Wallace Wright.

Be interesting to see the TV ratings for the worst of the exhibition games locally. The University of Pittsburgh was playing its home opener Thursday at Utah, giving fans in Western Pennsylvania every excuse not to watch this display.

These games make you long for the Pirates, and not even the good ones from 30 years ago.