PITTSBURGH - Bill Cowher and Jeff Fisher have been head coaches a combined 25 seasons, almost a lifetime in the what-have-you-done-for-me-this-minute world of the NFL.

The stars of the Tennessee Titans and Pittsburgh Steelers - Keith Bulluck and Hines Ward, Steve McNair and Joey Porter, Drew Bennett and Alan Faneca - have been rivals almost since the day they were drafted. The series once defined the old AFC Central, dating to the Titans' days in Houston, and remains spirited even removed from the boundaries of divisional play.

Remember the Titans' overtime playoff win 2½ years ago effectively decided by a roughing-the-kicker penalty? The scary Tommy Maddox injury that briefly left him paralyzed? Cowher's first win as the Steelers' coach, a 1992 upset in Houston helped along by a fake punt call? The Steelers' consecutive AFC title game wins over Bum Phillips' Oilers to close out the 1970s?

"I can't think of a better place to open a season aside from here at home than in Pittsburgh," Fisher said, and not just because the Titans have won four of five there.

For all their familiarity, however, what the Titans and Steelers don't know going into Sunday's opener is much about themselves.

The Titans know they're not the team that went 5-11 last season - they certainly hope not, with the NFL's youngest roster and 25 new players since two years ago. The Steelers want to be the same team that went a franchise-best 15-1 last season before losing to New England in the AFC championship game, but they didn't resemble it during a preseason in which their offensive starters didn't score a touchdown.

"We're still growing as a football team," Cowher said. "We're still evolving, we're still trying to create that chemistry."

So are the Titans, who have a new offensive coordinator in Norm Chow, a 32-year college coaching veteran, and many new faces after losing players such as Derrick Mason, Samari Rolle, Kevin Carter, Jevon Kearse and Eddie George the last two years, mostly for salary cap reasons. They expect to have four new starters on defense, though first-round draft pick Adam "Pacman" Jones won't start the opener at cornerback.

The Steelers kept their team nearly intact, but their opening day lineup won't look like it. Jerome Bettis and Duce Staley, with more than 1,700 yards rushing last season between them, won't play because of training camp injuries. That leaves the offense mostly in the hands of quarterback Ben Roethlisberger, who went 13-0 as a rookie last season but is starting his first opener, and running back Willie Parker, who has never started an NFL game.

The Titans knew so little about the former college backup, except for his 102 yards against Buffalo in January, they had former North Carolina teammate Michael Waddell talk to the team about a back who gained only 181 yards in his final college season.

The Steelers have seen enough long runs from Parker in practice to know he's a threat if he gets outside.

"We're still going to run the ball first and set up our pass game through the run game," Ward said. "That's our identity, and we're not going to change that because Duce or Jerome's injured."

The Titans also have two 1,000-yard rushers, Chris Brown and the newly acquired Travis Henry, but couldn't get both on the field at the same time in exhibition play because of injuries. Brown is expected to start after gaining 1,067 yards in 11 games last season.

"I think the running game could very well determine the outcome," Fisher said.

If not, Roethlisberger's passing very well could - one way or the other. He's coming off his playoff comeuppance, when he threw five interceptions in two games, and a ragged preseason in which he completed fewer than 50 percent of his passes and was intercepted twice.

He is also without his favorite receiver, Plaxico Burress (signed with Giants) and four-time Pro Bowl receiver Ward barely played during the preseason. As a result, Cowher said the rusty passing game is his No. 1 concern, and the team signed former Cowboys receiver Quincy Morgan five days before the opener to give Roethlisberger a deep threat.

"But I'm not nervous," Roethlisberger said. "I haven't been for any game yet."