PITTSBURGH (AP) At 6-foot-6 and more than 300 pounds, Pittsburgh's Stephon Tuitt can be difficult to move off his right defensive end position.

However, if the Steelers maligned defense is going to improve - especially the pass rush - Tuitt will need to make an impact during his second NFL season.

Tuitt started the opening three preseason games, but missed the last two because of a left foot injury that forced him to wear a boot for several weeks. He practiced for the opener against New England, and now he's ready to take his game up a notch when the Steelers host San Francisco on Sunday.

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''The foot feels good, and it's getting better every week,'' Tuitt said. ''I'm ready to jump right in. I'm the type of guy who believes everything happens for a reason. Things that you can control are your attitude and the way you prepare yourself for the battles you face each week.''

Tuitt had only one assisted tackle against the Patriots, so it wasn't a banner day for the Notre Dame product. But third-year linebacker Jarvis Jones believes it's only a matter of time before Tuitt contributes to the team.

''Tuitt's going to be a terrific player really soon,'' Jones said. ''He's got a great motor. He's getting very comfortable within the defense and playing faster than he ever has, so I think he's going to be great.''

With second-year player Ross Cockrell joining the cornerback rotation, the Steelers defensive backfield will be slightly different from the one Tom Brady burned for four passing touchdowns in the Patriots' 28-21 win last week.

Cockrell, a fourth-round pick by the Buffalo Bills last year, played seven games for them before being released. He signed with the Steelers just five days before their game against the Patriots and didn't play, but Cockrell has been in the thick of it this week.

''I did run with the ones most of the week, but I also ran with the twos and did a little scout team,'' Cockrell said Friday. ''I was all over the place. I did have a couple reps off, but I got some good work in practice this week.''

Cornerback Cortez Allen, who was the third corner last week, is listed as questionable against the 49ers with a knee injury. Cornerback Brandon Boykin has been limited most of the week with a groin injury, although he is listed as probable.

Notes: The injury report has safeties Mike Mitchell (hip) and Will Allen (concussion), inside linebackers Ryan Shazier (knee) and Sean Spence (hamstring) and quarterback Landry Jones (concussion) all listed as probable.