The Celtics are the worst second-quarter team in the NBA.

The previous sentence isn’t my own sentiment, but Paul Pierce’s. Yet I could hardly argue with him. The Celtics almost inevitably flush the second quarter down a toilet, and it’s mostly because of a bench that was supposed to be one of Boston’s strengths. The bench — that damn bench — gives away leads like Santa passes out gifts. According to Chris Forsberg, the Celtics bench has now been outscored in eight of its last nine games.

After watching the Celtics’ latest bench meltdown against the Raptors on Friday, Doc Rivers addressed the difference between the first and second unit.

“It’s unfair, but let’s be unfair for a second,’’ Rivers told the Boston Globe. “The first and third quarter, they scored 35 points on our starters. And you can make that case, especially in the third quarter because they played the whole third quarter. The other two quarters were 32 and 34, and that’s our second unit. So that was the only thing I talked about after the game.’’

First, I agree with Doc. The bench has been poor. I don’t think anyone in his right mind would argue that. Other than Davis, the bench’s other “contributors” have been inconsistent at best. But can we expect much more?

Jermaine O’Neal has missed nine games already. Shaq has missed five. Delonte West has missed all but five.  Kendrick Perkins hasn’t played a single second yet, Semih Erden’s battling through an injured shoulder, and Avery Bradley — the C’s first-round pick — has contributed all of six minutes in his NBA career to date.

Somehow, through all that, the Celtics are still winning games. Somehow, through all that, the Celtics stand atop the Eastern Conference. Is it fair to be so harsh toward the bench, when so many key players have missed games? Is it fair to be so harsh, when the team’s depth has been part of the reason it has overcome so many injuries to still be 12-4?

I’m asking real questions here. What do you guys think?

Glen Davis thinks there are no excuses.

“We’ve got to get it together,” Davis told the Boston Herald. “We have to make sure that we do what we have to do.

“There’s no excuses. We may not have the guys we thought we’d have – or all the guys we’re going to have – but we can still go out and play well and have a positive impact on the game. That’s on us.”