Updated

By Jahmal Corner

LOS ANGELES (Reuters) - If the Boston Celtics are to conquer the Los Angeles Lakers and raise an NBA-leading 18th championship banner to the rafters they will have to do it without starting center Kendrick Perkins.

Perkins, the team's defensive enforcer and key rebounder, has been ruled out of Thursday's decisive Game Seven in Los Angeles with multiple ligament sprains in his right knee suffered during Tuesday's Game Six.

"Well, he's not going to go. I'll tell you that now. We'll figure out the match ups later," Celtics coach Doc Rivers told reporters on Wednesday.

The Celtics will likely start either Glen Davis or veteran Rasheed Wallace in place of Perkins as they attempt to rebound from Tuesday's 67-point performance that was the second lowest offensive output ever in an NBA Finals.

"Everyone knows what they have to do - for us to accomplish what we want we have to do it on their floor," said Boston's Ray Allen. "We play well with our backs against the wall."

In Game Six in Los Angeles, the Lakers' bench was revitalized behind strong reserve performances from Lamar Odom, Jordan Farmar, Sasha Vujacic and Shannon Brown.

"Historically, your bench is much more comfortable on their home floor," said Los Angeles coach Phil Jackson, who is facing his first Game Seven in an NBA Finals. "I was happy with their purpose and direction."

Leading the way for Los Angeles in the pressure-packed deciding contest will be Spanish forward Pau Gasol along with four-time champions Kobe Bryant and Derek Fisher.

"It's a game we have to win; simple as that," Bryant said. "The opportunity is not something that makes me happy - what makes me happy is winning."

(Editing by Frank Pingue)