PITTSBURGH — Four important players in four different quarters – center Sean Mahan, linebacker LaMarr Woodley, running back Carey Davis, and defensive end Ryan McBean.

They were the focus last night in the Steelers’ 13-9 loss to the Green Bay Packers.

First quarter

Mahan had only two days of practice – and really only two practice days in the spring – with the first team, but on the first play Saturday night he fired out to block linebacker A.J. Hawk and Najeh Davenport ran up the middle for a five-yard gain. It became a theme for Mahan, who appeared natural at center as he bolted out to the second level and handled the inside backers – mainly Nick Barnett – every time he was asked.

Mahan picked up a delayed blitz from Barnett on the play Ben Roethlisberger was sacked and stripped of the ball. It was the only blitz Mahan saw as he played the rest of the first quarter without a negative.

In the second quarter, the Steelers used Max Starks at left tackle, giving the O-line an almost completely new look.

The only constant from last week’s starting line was Kendall Simmons at right guard, probably to develop some chemistry with Mahan. So, even though he’s played so little with the first team, Mahan appears to be the man to beat for the center job.

Mahan didn’t get a chance to show he could get downfield in front of a screen as well as Chukky Okobi, but Mahan was a plus in the run game against the Packers’ 4-3 and he wasn’t beaten in pass protection. The Steelers may have found their man.

Second quarter

With James Harrison being held out, Woodley started at linebacker, giving the rookie a great opportunity to take a job from the unspectacular Clark Haggans.

In the first quarter, Woodley couldn’t get much pressure against tight end Bubba Franks, but he once again showed adequate coverage skills, a surprising asset for the 265-pounder.

Woodley was the nose tackle on the punt-return team, and even threw a great block to flatten a man. It allowed Cedrick Wilson to turn the corner on a long return that was called back because of a penalty.

Against second-teamers in the second quarter, Woodley put more heat on the quarterback.

He even threw Franks to the ground as he pursued a running play up the middle.

Woodley played some middle linebacker on the third-down defense, but couldn’t blitz his way past the center or guard on two attempts. His best play occurred late in the half. On the touchdown that was called back because of a penalty, it was Woodley who bolted past the right tackle, grabbed the quarterback’s jersey and chased him out of the pocket.

Third quarter

Davis made the tackle on the opening kickoff, which showed both ability and his status with the staff. He was also on the first punt team and his two blocks helped spring Wilson’s 15-yard return in the second quarter.

The Steelers looked at Davis at fullback, and in the second quarter he sprung Kevan Barlow for a 17-yard run around right end.

Davis lined up in the slot, went in motion, and crabbed back to the perimeter to spring the man he’s competing against for a job.

The staff likely saw enough rushing skills from Davis last week. Saturday night he showed them he can play special teams and also lead-block.

Fourth quarter

McBean is another fourth-round defensive lineman in a fight for a job. The Steelers cut Orien Harris last year and McBean is far behind in his understanding of the playbook.

He could fall victim to the numbers game, even though defensive line coach John Mitchell loves his potential.

At left defensive end, Nick Eason held his precarious edge over Shaun Nua for the sixth job on the D-line. An injury to Chris Hoke could open the door for McBean, but it doesn’t help the team at all.

McBean entered the game late in the third and his quickness was evident right away. He beat his man on the first play and forced a tackle-for-loss on the third.

McBean remained a force through the fourth quarter.

Whether he was carrying out his assignments wasn’t known, but McBean made it clear – with his quickness and strength – why Mitchell likes his raw skills.