Frustrated Allen cuts backdoor

When the consummate professional is angry, he doesn’t lash out in the media or bare his soul when his emotions are raw. He slips out of the back of the visiting locker room at Conseco Fieldhouse, nearly jamming his nice travel bag in the door, pulling it through so hard that a piece breaks off and falls onto the floor.

Ray Allen kept walking, hardly concerned about the condition of his bag, more consumed by his lack of involvement in the Celtics’ offense and the team’s struggles to score down the stretch. The Celtics lost to the Pacers, 107-100, last night and once again Allen was hardly a factor in the offense.

He logged 36 minutes and attempted just eight shots, scoring 11 points.

It’s not that Allen wants Kevin Durant-like numbers of attempts, but he wants to be more involved in the offense in the early going, allowing him to gain rhythm for the critical stretches in games. Last night was a perfect example of how Allen is becoming less of a factor in the offense.

Through three quarters, Allen attempted four shots, making three for 8 points. Glen Davis took nine shots through three periods. Rajon Rondo attempted 13, which is understandable because it was one of those rare nights when he attacked the basket with success.

But in the fourth quarter, when the Celtics’ defense began breaking down after a brilliant third quarter, they needed instant offense and called on Allen for four shots in the period. He made one.

Allen needs more than four shots in the first three quarters of any game, especially as the Celtics’ best perimeter shooter by far. He sent a message last night with his slipping out the backdoor, but he may be out of explanations for why his role has been diminishing.

The Celtics’ offense is disjointed because Paul Pierce has been attempting more 3-pointers than Allen, and converting a lower percentage. Pierce has launched 33 in the past seven games, compared with 30 for Allen. Pierce has made 10 to Allen’s nine.

“We’ve got to make up our minds right now,’’ Pierce said. “This is a weird time to be talking about with nine games to go in the season. This is the type of stuff you talk about at the beginning of the year. We’re about to get into the playoffs and we shouldn’t be talking about this stuff. It’s just mental, how bad we want it going into the playoffs. We can’t think about what happened last year and ease into the Finals. That’s not going to happen this year.’’