The Celtics played their home opener Friday night against the Detroit Pistons, and Pierce was in the starting lineup.
"I was expecting to be me," said Pierce. "I don't settle for anything less. I worked tremendously hard, I did a lot of things -- I did what I could do, coming into the game, as much as I could, other than practice. I just stayed focused, I got my shots every day, did the bike. Doc wanted me to be aggressive, and play the way I play. That's what I tried to do."
Coach Doc Rivers said the winless Celtics' record did not affect the decision.
"We could be 3-0, I would be playing Paul tonight; We could be 0-3 and we would play Paul tonight," said Rivers.
Earlier this week, Rivers had said the earliest Pierce could return was Friday, but the Celtics' coach didn't make any promises. Coming off three games in four nights to start the season, the Celtics were given Thursday off and were not scheduled to reconvene until a pregame walkthrough at TD Garden before Friday's game.
Without Pierce, the Celtics started 0-3 -- their first such start since the 2006-07 season.
Pierce injured his heel during the team's first practice session of training camp and has been sidelined since. He went through a workout Monday and experienced less soreness than he had previously after ramping up his activity, and did some shooting Tuesday before the Celtics took on the Miami Heat.
Pierce chipped in 12 points Friday night.
Said Kevin Garnett: "The scoring overshadows the small things that he does. He's a very, very good teammate and a personal friend for a long time. He has a very, very high basketball IQ, and he's very talkative on the court. He knows how to play. And he's willing to give the ball up on his own. When you make sacrifices like that you impact everybody. It just gets overshadowed sometime by the scoring."
Sasha Pavlovic started in Pierce's place in each of the team's games against New York, Miami and New Orleans, averaging 4.0 points and 1.7 rebounds a game.
Chris Forsberg covers the Celtics for ESPNBoston.com.