Second-year center Darnell Stapleton, who also plays guard, will serve as Hartwig's backup.

They signed veteran tight end Sean McHugh to replace Mahan on their 53-man roster. McHugh, 26, was released by the Detroit Lions, where he started both at tight end and fullback last season. He will serve as the No. 3 tight end in Pittsburgh.

Veteran Mitch Berger is the new punter, and he also will hold for Jeff Reed's placekicks. Mewelde Moore and Santonio Holmes will return punts and Rashard Mendenhall will return kickoffs.

Backup quarterback Charlie Batch went on injured reserve and Byron Leftwich is No. 2. However, rookie Dennis Dixon could be No. 2 on some game days so they can take advantage of his ability to run.

PLAYER NOTES

--WR Limas Sweed will open as the No. 4 or No. 5 receiver after failing to provide any competition for the No. 3 job Steelers coaches thought he could become when they drafted him in the second round this year.

--LB James Farrior, who received a five-year contract extension last week, will wear the radio helmet on defense. Farrior, voted the defensive captain again, never leaves the field on defense.

--OT Max Starks will be paid $7 million guaranteed this year and might not even dress for games. The Steelers are considering dressing Trai Essex, who also can play guard, as their backup tackle.

--LB Larry Foote, who missed last week with a knee injury, returned to practice Monday and will start over Lawrence Timmons as the mack inside linebacker. Foote has not missed a game in the past four years as their starter.

--OLB James Harrison, the team's sack leader and MVP last year, will get the green light to roam a little more out of his position before the snap of the ball. Harrison made the Pro Bowl in his first season as their starter.

GAME PLAN: Double-team Mario Williams to keep him off Ben Roethlisberger and hit him with some draws and screen passes. As usual, the Steelers want to run the ball and will use Willie Parker extensively. However, they are a more diverse offense this season and coordinator Bruce Arians will want to display that diversity. On defense, they must contain wide receiver Andre Johnson but their most difficult job might be to stop rookie RB Steve Slaton. Pittsburgh's defense has problems with cutback runners and Slaton is one of the best at that.

MATCHUPS TO WATCH: Steelers LT Marvel Smith vs. Texans RDE Mario Williams, second in the AFC with 14 sacks last season. Smith feels good and has played better since December surgery to remove a herniated disk from a nerve in his lower back.

Texans return man Andre Davis, who had three kickoff returns for touchdowns last season, vs. the Steelers kickoff coverage team that ranked among the worst in the NFL last season.

Texans WR Andre Johnson vs. Steelers CBs Deshea Townsend and Ike Taylor. Johnson has made two Pro Bowls, Steelers corners none.

INJURY IMPACT:

--LB James Harrison returned to practice full time on Thursday and coach Mike Tomlin said he's fine. Harrison, the team's MVP at right outside linebacker last year, missed part of practice Wednesday with his shoulder in a wrap.