Luke Petitgout suffered a concussion during last week’s loss to the Bears, but the injury wasn’t the only reason his head hurt.

“We as a line made a couple of mistakes, and things just got out of control,” Petitgout said of the game in which the Giants were on the verge of a 21-0 lead in the second quarter only to suffer their worst defeat of the season. “This week, we’ve got to finish them. Finish them in every aspect: every block, every play, everything. And then finish them on the scoreboard.”

The Giants – and the offensive line, in particular – got some positive news yesterday, when Petitgout returned to practice for the first time this week.

His presence, coupled with the return of Shaun O’Hara from a leg infection that kept the center out the last two games, should diminish the chance of a repeat of last week’s disastrous showing against the Bears when the Giants visit the Cardinals tomorrow.

The line’s inability to protect vulnerable quarterback Kurt Warner helped do in the offense. Warner was sacked seven times, bringing the total over the last three games to 18.

“It’s our job to protect the quarterback, and any time the quarterback gets sacked seven times in a game, it’s hard to go out in public,” O’Hara said. “That’s on us; we’ve got to protect him. Everybody wants to get on Kurt, just like everyone was getting on the offensive line in camp. We’re standing up for him, this is a team.”

The members of the beleaguered line sounded confident that last week was an aberration and that they are not going to revert to the preseason form that caused many to write the team off before its encouraging start.

It only took one bad game for many of the questions that surrounded them during the summer to return.

“It just seemed like nothing went right,” Jason Whittle said of the 28-21 loss to the Bears. “We just have to play better all together. We had a breakdown here, a breakdown there. We took turns screwing up. When you do that, it makes for a long day.”

O’Hara’s presence tomorrow should solve at least some of the problems. His improvement during the week took head coach Tom Coughlin by surprise.

“At the beginning of the week, I expected him to take about half the snaps,” Coughlin said. “But he took pretty much all of them.”

O’Hara’s health will go a long way in determining whether Coughlin winds up being more pleased with the line.

“I thought our offensive line last week did poorly as a group,” Coughlin said. “So when we put some of those pieces back together, I think that’ll be a plus.”

It had better be. The Giants can’t afford to struggle like that again.

“The quarterback got hit, we had penalties, we did everything wrong,” David Diehl said. “But the great thing is we came back, looked at what we did wrong, and now we can redeem ourselves.”

That’s what they intend to do.

“From an offensive line standpoint, any time you give up seven sacks you can’t be happy,” O’Hara said. “That’s one thing we have to correct. I don’t care what they play or what’s going on. If the defense has everybody covered, we have to block our guys until the quarterback gets rid of the ball, whatever that takes.”