The Pittsburgh Steelers had the NFL's top ranked-defense and lost only two games in 2004. After they fell just one victory shy of the Super Bowl, no one would have blamed Pittsburgh's front office for signing a bunch of free agents in hopes of clearing that final hurdle. But the Steelers took an interesting offseason approach -- they didn't do much of anything.

Of the 20 Pittsburgh defenders with at least 10 tackles last season, 19 are back with the team in 2005. Only cornerback Chad Scott (29 tackles), who missed half of 2004 with a knee injury, was released. The idea, obviously, was to maintain continuity and depth on a defense that allowed an NFL-low 81.2 rushing yards per game.

"I like the depth that we have right now [on defense]," Steelers Coach Bill Cowher told reporters during camp. "How it transfers in the regular season, let's wait and see."

The Steelers may have to rely on that depth because of injuries. Pro Bowl linebacker Joey Porter had surgery on Aug. 10 to remove cartilage from his hyperextended knee. Porter (53 tackles, seven sacks) was slated to miss the entire preseason but hopes to return for the regular season opener. James Harrison (45 tackles) assumed Porter's starting role.

Depth is also a factor at cornerback, where several quality players are battling for playing time. Deshea Townsend (four interceptions) and Willie Williams (13th NFL season) started the first two preseason games. Close behind them on the depth chart are Ricardo Colclough, Ike Taylor, and second-round draft pick Bryant McFadden.

While Pittsburgh's defense remained mostly intact, the offense lost a few key parts from last year's unit. Those departures, along with injuries, have caused some concern entering the regular season. Wide receiver Plaxico Burress, who led the team with five touchdown receptions, departed via free agency to the New York Giants. Former San Francisco 49ers wideout Cedrick Wilson replaces Burress, but he has only 1,203 receiving yards in four NFL seasons. Starting offensive linemen Oliver Ross and Keydrick Vincent also left through free agency.

Injuries have clouded the Steelers' running back situation. Running back Duce Staley (830 yards) had surgery similar to Porter's during training camp, and his recovery is expected to continue into the regular season. Jerome Bettis, who rushed for 941 yards and 13 touchdowns in Staley's absence last year, injured his calf in a preseason game against the Redskins and might miss the regular season opener. Undrafted second-year tailback Willie Parker would start if Bettis can't play. Parker played in only eight games as a rookie, carrying 32 times for 186 yards.

Linebacker Joey Porter is hoping

to flex his muscle after surgery.