After the knee injury, Speights' effectiveness - and his minutes - diminished.
This season, Speights strained his right hamstring in a preseason game at Toronto.
Since then, he hasn't seemed like the same player.
"I think Mo, when he gets nicked up a little bit, it really affects him . . . ," Sixers coach Doug Collins said. "I would just see him running in practice and just reaching and checking his leg out. It was brought to my attention it was [what] he did last year when he got injured."
Collins said he might be as unhappy as anyone that Speights has started so poorly.
"Mo has had such a great summer," Collins said. "It's disappointing."
Against the Pacers, Collins removed small forward Jason Kapono from the starting lineup, replacing him with Andres Nocioni.
In the team's first two games, both at the Wells Fargo Center, Nocioni averaged 12.5 points and demonstrated a toughness the team has been lacking since trading forward Reggie Evans to the Raptors before the 2009-10 season.
When asked about becoming a fan favorite, Nocioni said, "That's good for me."
"I think we try to play hard this year and try to win games, and that's my style," he said. "That's how I play; I try to bring my energy every night."
Collins kept rookie forward Craig Brackins and second-year guard Jodie Meeks on the inactive list, where they have been since the season started last week.
Collins explained the choices, saying that the team was looking at Brackins as a "red-shirt freshman," and that Meeks' role of "designated shooter" already is occupied by Kapono.
- Kate Fagan