On a scale of do, re, mi, fa, so ... here are five keys to the continued success of the Steelers as they bid for an unprecedented sixth victory in the Super Bowl. None, they hope, will be played in the key of B-flat:

1. Big Ben
Forget the header he took June 12 on Second Avenue, Ben Roethlisberger will remain a key to any future season with the Steelers. Yes, he has arrived after just two seasons. Quarterbacks seldom get off to the kind of start this 24-year-old did and then go bad or even mediocre, and there's no sign he will join that minority.

The issue for Roethlisberger is how healthy he can stay. He missed four starts with two knee injuries last season, games the Steelers split 2-2. He also played down the stretch with a protective sheath covering a sprained right thumb that seemed to affect his passing performance in just one game, a Dec. 4 loss to Cincinnati.

He proved in the playoffs that the team can win with him throwing the ball and not just by handing it off. They have expanded that part of the playbook and will continue to give him a longer leash in terms of audibles and having a bigger say in the game plan.

2. On the run
For a team that ran more often than any other in each of the past two seasons, the depth can be worrisome. Willie Parker proved no fluke last season and that he can reliably carry 250 times without breaking down.

Someone, however, must replace those grueling 110 carries by Jerome Bettis, who received the call mostly near the goal line or in the second half of games when defenses stacked against the run. It's what they call the tough yards. Parker might add some of those carries, and Duce Staley and Verron Haynes want to fill the old Bus role.

Still, you don't just subtract someone like Bettis without replacing him on the roster and have as good a backfield. Staley's return to top form -- or at least the one they saw in the first half of the 2004 season -- would go a long way toward easing the concern here. And it is a concern, or the Steelers would not have talked to Atlanta during the draft about a trade for T.J. Duckett.

3. Backup wide receivers
A cause for worry one year ago was the loss of 6-foot-6 Plaxico Burress and how it would affect Roethlisberger and the offense. Not much, as it turned out. A key this year is whether the loss of Antwaan Randle El, who replaced Burress, will affect the offense. The Steelers look for a repeat performance.

Cedrick Wilson steps into the swinging door that has become the split-end spot, the one opposite flanker Hines Ward. The Steelers peppered draft choices at the position last spring, taking Santonio Holmes in the first round and Willie Reid in the third. Those two will make the team and could help out at some point this season. But they're both behind Nate Washington, a second-year player who played at Tiffin University and went undrafted. Washington caught one pass last year, an important one in the AFC championship game. But other than Quincy Morgan, there is virtually no experience behind Ward and Wilson.

4. Good night
The Steelers are Prime Time's Team, and we're not talking the favorite of Deion Sanders. They open the season with consecutive night games -- Thursday and Sept. 18 at Jacksonville. Three of their first four games come at night, including an Oct. 8 return visit to San Diego.

They have another Dec. 7, a Thursday, against Cleveland (Alan Faneca's 30th birthday, by the way) and six of their remaining games are subject to be moved from 1 p.m. Sunday to 8 p.m. at the behest of NBC. Provided the Steelers remain in contention, their Nov. 26 game at Baltimore, Dec. 17 game at Carolina and the Dec. 31 finale at Cincinnati rank high on possible night moves.

The Steelers have played to mixed results in prime time. While they are 18-7 overall (but just 8-6 since 1997) under coach Bill Cowher in Monday night games, they are just 7-6 on Sunday nights (3-4 since 2000) and 0-2 on Thursday nights since 1992.

The schedule appears to be much more difficult than the one that launched them to a Super Bowl victory last season. They opened with softies Tennessee and Houston in 2005. This year, they go against Miami at home and at Jacksonville before an early AFC North showdown against Cincinnati. They have road games at contenders San Diego, Atlanta, Baltimore, Carolina and Cincinnati and must play in that snake pit that serves as Oakland's home. Toss in Heinz Field appearances by AFC championship opponent Denver, AFC contender Kansas City and NFC contender Tampa Bay, and it's one brutal card. At least Cleveland appears twice.

5. Good luck
In 2003, the Steelers ran into injuries and bad luck and went 6-10. This came after their playoff season of '02 and before their 15-1 record of '04. Bad luck can ruin a good team's season and good luck can uplift a ballclub, although there's nothing that will help a bad team.

The Steelers need only look at 2003, or 1976. That was the team many, including franchise founder Art Rooney, claimed was the best in its history. Yet they started a 14-game season 1-4. Although they did not lose another game and were overpowering as the playoffs began, three of their backs, including Hall of Famer Franco Harris, were hurt in a 40-14 playoff runaway at Baltimore. They had virtually no backfield in Oakland the following week and lost in the AFC championship, 24-7, and the "greatest" team in Steelers history never reached the Super Bowl.

Stuff happens. The Steelers were fortunate last season, not only to beat San Diego, 24-22, on Jeff Reed's 40-yard field goal with six seconds left, but also that Roethlisberger's knee injury near the end of the fourth game was not more serious. He could have been lost for the season, and instead of a Super Bowl, the Steelers might have gone 8-8. An NFL team needs to be good and lucky to win a championship.