PITTSBURGH - Being a backup for the first time in his career last year didn't necessarily prepare Jerome Bettis for being one again this season.

Bettis knew the Steelers didn't bring in former 1,000-yard rusher Duce Staley to sit him. He also knew the Steelers didn't cut his own salary by nearly three-quarters, to $1 million, to give him the ball 25 times a game.

Regardless, the No. 6 rusher in NFL history was disappointed when he officially learned he's No. 2 on the depth chart going into Sunday's opener against Oakland.

"I'd be lying to you if I said, `Uh, yeah, it doesn't affect me,' " Bettis said Wednesday. "It affects you. It's disappointing, make no mistake about it, but you understand it.

"If you say, `Did last year gave me a better understanding of a situation like this?' Yeah. Did it help me prepare for it? No," Bettis said.

Cowher's decision to start Amos Zereoue a year ago wasn't surprising because the Steelers were making the transition from a running to a throwing team. The changeover, masterminded by former offensive coordinator Mike Mularkey, flopped as the Steelers went 6-10 and Zereoue (433 yards, 3.3 average) was released after the season ended.

The Steelers are back to their traditional run-it-first mentality, but the 32-year-old Bettis isn't back in the lineup despite having two 100-yard games in December - one against the Raiders.

"I can't worry about that," Bettis said. "The deal was done. I have no regrets, that's what I'm happy about and comfortable with. I gave them everything they wanted to think about in training camp, I made it tough on them."

Cowher insisted there is no predetermined plan for how Bettis will be used, and Bettis said he hasn't been promised a certain number of carries.

"We got involved in one series in the preseason where we got into a long drive and Duce was on the field and he came off the field and Jerome ran in there for a couple of plays," Cowher said. "I think it's a healthy situation and, hopefully, we'll be able to get them both involved."

Despite playing behind Zereoue for six weeks, Bettis outrushed Staley 811-463 last season as Staley split playing time with Bryan Westbrook and Correll Buckhalter in Philadelphia. Staley came to Pittsburgh to carry the ball more, and if that occurs, it will mean far fewer carries for Bettis than the 246 he had last season.

The Steelers also plan to use another back, Verron Haynes, in some third-down situations, and undrafted rookie Willie Parker unexpectedly made the 53-man roster after running for a team-high 202 yards in four exhibition games.

"It's different in the sense it's a different guy (ahead of him), but it's still a tough situation because you would like to be out there," Bettis said. "But you've got to stay focused, stay positive, because this team is going to need me at some point."

Notes:

Bettis had two 100-yard games in Pittsburgh's three games against Oakland since 2000. ... QB Brian St. Pierre was added to the practice squad after clearing waivers. He was let go when the Steelers claimed special teams standout Sean Morey off waivers from Philadelphia. ... DL Nathaniel Adibi, a fifth-round draft pick, also went on the practice squad after being waived by Tennessee. The Titans picked him up after the Steelers released him.