For almost a half of basketball, Paul Pierce had something of an identity crisis. Should he be the passer and facilitator that he was while Rajon Rondo was out of the lineup, or should he be the lead scoring option, a role that has defined the majority of his career? 

Pierce took only four shots in the first 22 minutes of action against the Timberwolves Monday night and missed all of them. But late in the second quarter he got himself going with a couple of baskets. At halftime, Doc Rivers reminded him. “Paul you no longer have to be the playmaker,” Rivers told him. “We need you to be an aggressive scorer.”

Pierce went out and lit up the Wolves in the third quarter, scoring 15 points on only eight shots and helped kick-start the sputtering Celtics offense. After sitting out the first five minutes of the fourth quarter, he took only two shots when he returned, but his 3-pointer with 3:34 left broke a three-minute scoring drought for both teams and brought the Celtics within two points. All things considered, it was one of the biggest shots of the night.

“I was out there trying to make plays and I forgot that we had Rondo out there doing that so I can go back to my customary role of scoring the ball,” Pierce said. “That’s what I tried to do in the second half.”

Pierce calls this, “giving the game what it needs,” and it’s easy to forgive him for that well-intentioned first-half transgression. When Rondo sat out seven games with a severely sprained ankle, Pierce became the team’s point forward, often handling the ball and getting them into sets at the expense of looking for his own offense.

He did a solid job in that role, recording 10 assists against the Hawks on the first night without Rondo and 12 more against the Pacers in their next game, both Celtics victories. Pierce dished out a total of 47 assists over those seven games, and the Celtics won four of the first five, before dropping the last two, notable also for the absence of Kevin Garnett.

With Rondo back, Pierce dropped 53 points in wins over the Raptors and Timberwolves. He also acknowledge that his sprained ankle, suffered at the end of their win at Toronto Sunday, was bothering him a bit, but not as much as he feared.

That’s the only concern with Pierce because as the calendar turns to 2011, he is putting together his best season in the Big Three era. His shooting percentages are up, so is his defensive rebounding and his turnovers are at their lowest point of his career.

At 33 years of age, Pierce isn’t rediscovering the game that made him such a dynamic force early in his career. Rather, he is aging gracefully into an efficient scorer and all-around player. His defense, long an underrated aspect of the Celtics overall defensive success, has also remained constant.

This is all part of Pierce’s late-career transformation from  a high-usage franchise player/lone wolf to an integral part of a championship team. The dynamic between Pierce and Ray Allen, in particular, has been remarkably consistent during their time together, with each sacrificing parts of their game for the betterment of the overall team structure.

“Whatever this team needs from me or Paul, I think he feels the same way, we just have to figure it out,” Ray Allen noted last week. “If we have to score 10 points a game to make it happen or if you have to have 20, you’ve got to do what you have to do to make it happen. It’s important that everybody feels that way too.” 

Pierce, ever so subtly, has taken it up a notch this season. On first glance, his numbers aren’t all that different from the levels he’s established with Garnett and Allen as teammates – 19 points, five rebounds and about four assists per game. But dig a little deeper and you’ll begin to see some of the improvements this season.

He’s shooting over 50 percent from the field and 87 percent at the free throw-line, both career highs. He’s also making 3-pointers at a 39 percent clip, which have raised his True Shooting percentage (combining 2’s, 3’s and free throws) to .616, the highest mark of his career. In a sign of good health, Pierce is taking the ball to the basket and finishing at a rate (72 percent) comparable with Kevin Durant and LeBron James. (See how Pierce’s numbers break down at Hoop Data).

Pierce has also hit the defensive glass, where his rebounding percentage is at its highest-level since the 2006-07 season, part of the team-wide commitment to defensive rebounding that they feel lost them the championship last season. Additionally, Pierce’s net plus-minus is +15 according to Basketball Value, which ranks fifth in the NBA and underscores his importance.

This isn’t an overnight transformation. Pierce’s numbers since Allen and Garnett arrived have remained remarkably consistent over the last three and a half seasons, which is an achievement in its own right. Pierce made the adjustments in his game in 2007-08 and has gradually improved them to this point.

It’s worth noting that Pierce was also off to a great start last season before the injuries began to pile up. As he told ESPN’s Jackie MacMullan, they got so bad that he contemplated shutting things down. Stubborn as always, Pierce played on and his offensive numbers took a hit.

It’s possible that Pierce’s shooting percentages will fall a bit as the season wears on, but it’s his health that is the most important factor in sustaining his early-season success. As great as Rondo and Garnett have been, don’t discount Pierce’s importance to this team because he’s been the one who has not only done his job, but also picked up the slack in their absence.

“He’s a great guy to have on your team because he does so many things,” Rivers said back in December. “People just look at him as a scorer; and his IQ, he’s a very smart basketball player. He’s the chameleon. We would rather have him in the scoring mode all the time. With this team, with the injuries we’ve had, he’s been a phenomenal utility player for us.”