PHILADELPHIA -- Andrew Bynum did nothing more at Philadelphia 76ers practice than receive some slaps on the back.

His teammates tried to cheer up the center with a simple message: Hang in there.

Bynum wanted so much more out of the day he expected to practice for the first time with his new team. Bynum remained sidelined with right knee pain and is a long shot to play in the Oct. 31 opener.

His debut is on hold and no one knows when Bynum will return. He will continue to be held out of all basketball activity until he is pain free from a bone bruise he suffered during an offseason workout. The Sixers had pegged Wednesday as their franchise player's potential return date after a three-week layoff that cost him the entire preseason slate. Instead, Bynum was on the sidelines while the rest of the Sixers practiced and scrimmaged.

"He's a big investment for our team," Sixers general manager Tony DiLeo said. "We want to be cautious."

DiLeo said each day Bynum is out increases the likelihood the All-Star center will not be ready for the opener.

Bynum says he wants to be cautious with his return and will not play until he is pain free. He received an injection of Synvisc -- a gel-like substance that sometimes provides relief for inflamed tissue -- on Monday. The natural substance is designed to lubricate and cushion the joint.

Bynum will then work his way back into low-impact exercises after several days of rest following the injection.

"We just have to talk to Andrew every day and see how he's feeling," DiLeo said. "When he is pain free, that's when he will start basketball activities."

No one, from DiLeo to Bynum, cared to predict just how much more time Bynum will miss. But with the opener against Denver on the horizon, and Bynum yet to practice, the Sixers are prepared to go with Lavoy Allen at center.

Bynum failed to sound convincing when he said "there's a possibility" he could be in the lineup against Denver. He conceded the final decision is up to the Sixers. He won't rush back for the first week and risk injuring the knee to the point where he'll miss serious chunks of time later in the season.

"Everything's about the big picture," Bynum said.

With a history of knee injuries already behind him, Bynum said he feels no pain when he walks, just during physical activity. DiLeo said rest should help heal the bruise and the injury was not a "recurring thing."

Bynum is coming off his best NBA season after averaging career highs with 18.7 points and 11.8 rebounds while making his first All-Star team, starting for the West. He was the NBA's third-leading rebounder and 20th-leading scorer, while also ranking sixth in the league with 1.93 blocked shots per game. The Sixers acquired him from Los Angeles in a four-team deal.

Bynum has been quietly absorbing coach Doug Collins' system from the sideline.

"I think he has a very good handle on our personnel and what each guy does well and stuff," Collins said. "I think it's important, especially as a big guy -- when you're playing in that post -- to know the guys you're playing with."

Without Bynum, the Sixers went 6-1 in the preseason, giving them a needed confidence boost they can win without their 7-foot piece in the middle.

"We're not going to look over at a lifeline and say, `Let's wait for our lifeline to get back.' From a coaching standpoint, I have to let our players know we're good enough," Collins said. "We're good enough to win. That's who we can be.

"Hopefully when Andrew comes back we can be even better, maybe take it to another level."

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