PITTSBURGH (AP) The youth movement on the Pittsburgh Steelers' defense is accelerating.
Rookie end Stephon Tuitt could make the first start of his career on Monday night against Houston while massive nose tackle Daniel McCullers may find his way into uniform following a shoulder injury to Steve McLendon.
If Tuitt replaces veteran Brett Keisel, who is nursing a knee injury that kept him out of practice Thursday, then safety Troy Polamalu will be the only defensive starter over 30. Pittsburgh had five defensive starters 30 or older as recently as the 2013 season opener.
Defensive coordinator Dick LeBeau understands the overhaul was necessary, even if it's something the Steelers have largely avoided during his decade-long tenure. Still, the Hall of Famer believes Tuitt and McCullers can make a positive impact despite their limited experience.
''Anybody that's got the raw material these guys have got - Dan's got the size and strength, Tuitt has the athletic ability - they're going to be able to contribute and they've got to start right now,'' LeBeau said.
The Steelers (3-3) need them to mature quickly if they want to halt an erratic opening six weeks in which they have looked competitive one Sunday and confounded the next. The trend continued in a dismal 31-10 loss to Cleveland last week in which the Browns gashed Pittsburgh for 158 yards rushing and quarterback Brian Hoyer averaged 27 yards per completion.
The presence of Tuitt and the massive 6-foot-7, 350-pound McCullers won't solve all of the problems, but LeBeau is intrigued about the chance to see if Tuitt's heady play in practice transfers under the lights.
''He's going to be a good player, you can write that down,'' LeBeau said.
Tuitt's ascent has been steady since the beginning of training camp, when LeBeau threw the second-round pick onto the field with the starters to see if he could hold his own.
The results were promising, though Tuitt has done his best to keep his head down and wait his turn.
''Every week I choose to get better at something,'' he said. ''I try not to overwhelm myself, so this defense is starting to be understandable to me.''
Certainly looks like it.
There have been flashes of brilliance in practice. Tuitt jumped in front of a screen pass from backup Bruce Gradkowski last week and sprinted down the field.
The 6-foot-5, 303-pound Tuitt doesn't lumber so much as he leaps. Though he played along the interior at Notre Dame, the Steelers moved him to the outside to take better use of his speed and the kind of long arms that can clog up passing lanes.
The transition hasn't been easy. Pittsburgh requires all of their ends to learn how to play on both the left and the right.
''You've just got to be able to be focused and understand your assignment and who's coming with you,'' Tuitt said.
There's a chance McCullers could be along for the ride on a handful of snaps. Considered a project when Pittsburgh grabbed him in the sixth round of the draft, McCullers has spent most of the last four months redistributing his weight. The results haven't gone unnoticed.
''I think he's moving well for a man his size,'' said LeBeau, who added he'd be comfortable if McCullers was forced to play extensively.
McCullers said he's ''not at the full greatness that I can be,'' but is realizing the days when he could simply overwhelm an opponent are long gone.
''I'm getting better every week with my technique,'' he said. ''So, I'll keep working on my craft and try to get better as much as possible. I'm not there yet, but I'm going to keep working at it. And I'll get there.''
The sooner the better for McCullers. And his team.
NOTES: LB Ryan Shazier practiced for the second straight day. Shazier hasn't played since spraining his right knee against Carolina on Sept. 21. ... Keisel and S Mike Mitchell (knee) did not practice.
AP NFL website: www.pro32.ap.org and http://twitter.com/AP-NFL