Offensive lineman Darnell Stapleton continues to watch practices and coach Mike Tomlin continues to shed little light about what is wrong with his second-year starter.

Stapleton has a left knee injury that has kept him from practicing since Sunday. He had at least one MRI (Monday), but Tomlin remains mum about what might be wrong with him.

"No new news with Stapleton," Tomlin said, and, when asked about him a second time, said, "Again, when I'm ready to talk, we'll talk about it."

Stapleton, who started 15 games at right guard through the Super Bowl last season, opened training camp at center for injured Justin Hartwig. Veteran backup tackle/guard Trai Essex has been at right guard and is likely to stay there, no matter what happens with Stapleton.

The problem for the Steelers is not at right guard, but with the versatility that Stapleton brings. Because he can play guard and center, he was the perfect swing man on game days even if he lost his starting job to Essex, who can play guard and tackle.

Two days after quarterback Ben Roethlisberger mentioned that his arm was giving him problems, Tomlin rested him during the afternoon practice.

The coach said there was no correlation, that he planned it that way. "I just scheduled to rest this guy some in training camp and took an opportunity to do it this afternoon."

Tomlin wanted to make one thing perfectly clear on a cloudy afternoon: It was as much a dress rehearsal for the fellows in uniform as it was a day off for the fellows out of uniform.

While "preserving the 30-year-olds" as part of his continuing policy, Tomlin noted how the defense went "without their quarterback," inside linebacker James Farrior, in the morning session. Defensive end Aaron Smith and running back Mewelde Moore likewise received a pass from the morning while Hartwig (toe) and tight end Heath Miller (sports hernia surgery) were limited. Then, in the afternoon, Roethlisberger was joined on the side by defensive end Travis Kirschke. Missing both practices were safety Troy Polamalu (hamstring), cornerback Deshea Townsend (hamstring), rookie defensive end Ra'Shon Harris (groin), receiver Hines Ward (shoulder surgery) and Stapleton (knee).

"More importantly with that ... it's not about the guys that you pull out of drills, it's the guys that you put into drills in place of them," Tomlin said. "When you take [No.] 7 out of the huddle, I was very interested to see how the offense operated. We'll just continue to do those kinds of things to take a look at our football team."

Four things stood out about rookie receiver Mike Wallace in the early days of training camp:

He has a Mohawk haircut, he has speed, he has a tattoo of the New Orleans Saints on his neck, and he dropped his share of passes.

The haircut can change, the speed is good and he has redeemed himself by hanging onto the ball lately. But a New Orleans Saints tattoo?

Few teams in the history of the NFL have had less success than the Saints, who are still looking for their first Super Bowl appearance. Wallace, on the left side of his neck, has "N.O." and the Saints emblem tattooed.

"They know I'm from New Orleans," Wallace said of his new teammates. "After [Hurricane] Katrina, I got this tattoo. It doesn't mean anything about football at all."

Turns out, he's not the only one.

Ike Taylor, who grew up in New Orleans, not only has the Saints' emblem beneath his left wrist, he has the city's name scripted across his chest. Taylor said other Louisianans such as Ryan Clark and rookie cornerback Keenan Lewis also have them.

Roethlisberger mentioned Wallace in each of his two post-practice comments since he arrived at Saint Vincent, one Saturday and one Monday.

"He's really fast, we just keep working on him catching the ball now," Roethlisberger said after the first camp practice Saturday. He followed Monday with, "Mike, No. 17, he's doing a great job of getting down the field. We just need him to catch the ball when he gets down there now."

Yesterday morning, Wallace made a nice catch in the corner of the end zone in a red-zone passing drill. "I had to get back to being in the flow of football again," he said. "We had a whole month off. I had to get used to it again. I feel I'm catching the ball pretty good and making great strides."

Late in practice, the field-goal unit pulled a fake in which Batch tossed a lovely go route to defensive tackle Scott Paxson

Even before the ball nestled in Paxson's short arms, teammates starting chanting his nickname -- T-Rex, for his trunk length and arm brevity -- and begging him to do a touchdown shuffle.

So he did the T-Rex Dance.

"They said I should learn a dance, so I did ... with short arms," said Paxson, who has served mostly on the practice squad parts of the past three seasons since leaving Penn State. "I'll do anything they want me to do to keep me here."