Since then, however, that optimism has been tempered. The 7-foot, 285-pound Bynum has been hampered by painful knees that have kept him from playing with his new teammates, extending the learning curve they will need to come together.
A free agent next summer who will earn $16.5 million this season, Bynum can sign an extension next February, or the Sixers can sign him to a five-year deal next offseason. That was something Sixers managing owner Josh Harris seemed more than eager to do before the state of Bynum's knees made him more of a mystery than a certainty.
Bynum won't be in the starting lineup Wednesday when the Sixers open the season against the Denver Nuggets at the Wells Fargo Center, and he will not play until he is, as general manager Tony DiLeo said, "100 percent pain-free."
Nobody knows when that will be.
Knees are a worry
While former Sixers star Charles Barkley wonders how Bynum will respond to being the Sixers' main man, his bigger concern is how healthy Bynum will be.
"He can't begin to answer the other questions about being 'the man' or being the leader on a team unless he can play," Barkley said. "So after that, everything else is secondary."
Despite having had surgery on both knees, Bynum appeared in 60 of 66 games last season. He missed four of those games because of a suspension, one to a sprained ankle and the other for rest. He had a career-best season in which he was named the starting center for the Western Conference in the All-Star Game.
The Sixers insist that the reason for Bynum's present discomfort is a bruised bone in his right knee. They insist it has nothing to do with the Orthokine injection therapy he received in Germany in September or the Synvisc-One shots - designed to relieve arthritic joint pain - a little more than a week ago.
More than two weeks ago, coach Doug Collins said that Bynum told him he could play if he had to. It was also two weeks ago that Collins first hinted that Bynum would not be ready for the season opener.
"I tried to play with two broken feet, and I wound up blowing out a knee that ended my career," Collins said. "This kid is  years old. We're going to listen to him and his body, and when he's ready to play he's going to be out there and playing. But I understand injuries, and I'm very much sensitive to those things.
"I know how important the home opener is. But we're not going to do anything where now it costs you during the season."
What Bynum could be
During a break between broadcasts at the London Olympics last summer, Collins and good friend, fellow former broadcaster, and current Boston Celtics coach Doc Rivers were discussing players who caused their teams trouble.
"I told [Collins] Andrew Bynum gives us hell," Rivers said, fewer than 24 hours before the four-team trade that delivered Bynum to the Sixers was consummated.
Despite the knee injuries that have contributed to Bynum's appearing in 65 games or more in a season just twice in his career, he has at times been dominant.
Teammates Dorell Wright and Jason Richardson have labeled him the best offensive center in the league. Shaquille O'Neal has said that Bynum is better than Dwight Howard, widely regarded as the best center in the NBA.
While he is not the defensive threat that Howard is, Bynum has a substantially larger offensive arsenal. The third option on the Lakers for most of last season, Bynum posted a 55.8 shooting percentage, his lowest in the six seasons he started in Los Angeles.
"He makes a tremendous difference," Rivers said. "He gets the ball in the paint, and it's a basket or a foul. A guy who does that allows you to set your defense up when you are at the free throw line, so it makes you a better defensive team, as if the Sixers needed to get better defensively.
Rivers said Bynum is a "run-killer."
"You can go on an 8-0 run, and they can call a timeout. You know where they are going to go out of the timeout, but you can't do anything about it," Rivers said. "That's what a big guy like that can do for you."
Since the 2003-04 season, Bynum is one of just four players - Tim Duncan, Kevin Garnett, and Howard are the others - to have averaged at least 18 points, 11 rebounds, and 1.9 blocks in a single season. Last season, he recorded 37 double-doubles, including two 20-point, 20-rebound games.
"Players like Andrew Bynum aren't just falling off trees," Harris said.
On the right track
The Sixers prepared throughout training camp and the preseason as if Bynum would not be in uniform for Wednesday's opener.
"It's important for us to get out to a good start with what we have," Collins said. "No one is going to feel sorry for us and our situation."
When Bynum is finally ready to play, Rivers said, it won't be difficult to work Bynum in because he will be setting up down low. That will augment what the Sixers are expected to do well - shoot from long range and cut off the perimeter.
When the time comes, Bynum must stay healthy and be ready to become the team's top option.
Lakers coach Mike Brown and Bynum clashed at times over the last two seasons. Brown said Bynum has the tools to be great. He just wondered whether he's ready to handle the mental side of it.
"He definitely has the size, agility, athleticism to go get it," Brown said. "Now it's a matter of whether or not and how long it takes him to figure it out. He was on the right track. I thought he grew a lot last year.
"This is now an opportunity for Andrew. Last year was his first step of being 'the guy.' He definitely has the attributes to get after it. It's whether or not he's going to go get it done."
Contact John N. Mitchell at firstname.lastname@example.org. Follow @JmitchInquirer on Twitter.