Duncan and the Spurs won, 90-85.
Bynum, in a soft, blue sport coat, his hair combed straight like, in his words, a cartoon pimp named Slickback, calmly watched as the 41st game of his eighth season unfolded without him.
By the time Duncan finished his eighth season, he had carried the Spurs to three NBA titles. In an age when swingmen sell the shoes, Duncan is the best argument for traditionalist wedded to the concept of playing the game from the inside out.
That's why the Sixers gambled.
The thrilling mirage of the Allen Iverson era set the franchise back years. The less tangible contributions of a player such as Andre Iguodala are lost on a fan base spoiled by home runs, touchdown bombs and NBA scoring champions.
So, the Sixers gambled with Bynum. They hoped to challenge the Heat and the Bulls.
The Sixers stand 17-24, out of playoff contention, sinking fast.
Bynum, the centerpiece of the trade of Iguodala, has not played a minute.
His chronically flawed knees have allowed him to do no more than shoot baskets with his team - a breakthrough realized only Monday morning, according to Bynum.
Next: Moving sideways!
Still, it was a gamble the Sixers had to make. With Duncan on his wane and with Dwight Howard clearly unsalvageable, Bynum is the only big man in the game capable of dominating; able to rule the boards, to score inside and out, to pass deftly and to shut down the middle.
Given health and a clear stage, Bynum could make Kevin Love look pedestrian.
The Sixers gambled on that.
At this point, they cannot win.
They are underwater in their investment, hopeful for any return at all.
"We have to see, first, if he comes back," said general manager Tony DiLeo, ominously, resigned, before the game.
"Then, when he comes back, how healthy he is and what kind of condition he's in."
Only then can the Sixers begin to assess whether Bynum, a $16.9 million burden, fits with their future. Or with anyone's future.
Bynum promises his best effort once his joints get better.
"Once I get back, I'm going to play really hard," said Bynum, who hopes for a mid-February return. "Play like it could be gone tomorrow."
No one expects Bynum, 25, to be finished. Not even the saddened Sixers.
"We can find out whether he can get back to the level of play he played at last year," DiLeo said of Bynum's only All-Star campaign. "How the players around him complement him. How he complements the players around him; how we structured the team, built the team."
They built the team expecting him to play in the All-Star Game, not to return by its intermission.
A mid-February return would leave 8 weeks for the Sixers to see Bynum play at something close to 100 percent. That is not long enough to know whether Bynum, unsupported, is a 20-point, 10-rebound player night in and night out.
When the Sixers made the trade, they prayed that ability lay dormant, stifled by the frontcourt presence of teammates Pau Gasol and Metta World Peace. Bynum never averaged more than 18.7 points or 11.8 rebounds, both highs hit last season, when the lockout shorted the season to 66 games.
Even fully healthy, can Bynum produce at that rate for 80 games? For 70, even?
Can he absorb the physical abuse, as the featured post player, that Shaquille O'Neal took, that Duncan took?
"That's a good question," DiLeo said. "We don't know."
Can Bynum endure the expectations that accompany the spotlight in a city less star-stricken than Los Angeles? He was, last season, perhaps the sixth most famous basketball player in LA, thanks to the Clippers' Lob City production and the eccentric Metta man.
Life as Public Entity No. 1 can be maddening. Ask Donovan McNabb. Ryan Howard. Mike Richards. Ask poor Andre Iguodala.
Will Bynum click with Jrue Holiday and Evan Turner and Thaddeus Young? Will he chafe under the harshness of coach Doug Collins?
In this moment, in Philadelphia, the trade feels fruitless.
It should not.
The changing of the guard that began in the playoff run last season ended when Holiday took the team from Iguodala. Without Iguodala's limited offensive presence, Holiday and Young blossomed into more complete players.
The club got a chance to look at Dorell Wright and Nick Young, a pair of intriguing talents.
And, well, that's about it.
As the season began with a soft schedule, there circulated a foolish contention that, even without Bynum, this iteration of the Sixers is better than the playoff team of last spring.
The Sixers are 7-18 since their 10-6 start.
Oh, well. Any gamble assumes risk.