Let's get this out of the way right from the start: Lawrence Frank is not Tom Thibodeau.

For one thing, the still boyish-looking Frank comes to the Celtics with the words "head coach" already on his resume after a mostly successful run over parts of seven seasons with New Jersey. Where Thibodeau was the defensive guru, Frank is more of an all-around aide to head coach Doc Rivers. There’s also the matter of personality.

“I’m not a doctor,” Frank said after helping conduct practice Monday while Rivers recuperates from throat surgery. “I look like one, but I’m not one.”

The punch line, of course, is that Frank bears a resemblance to Doogie Howser, a joke made often at his expense by Charles Barkley.

Rivers' absence allowed Frank to hold court with reporters for the first time in camp, and while he tried several variations on “it’s not about me” to various questions, it seemed like the perfect time to get to know him a little better.

What stands out about Frank is his self-deprecating sense of humor, and a quick, Jersey-guy wit. In that, he seems a bit more down to earth than the monastic, hard-driving image Thibodeau presented.

“A little more normal,” Paul Pierce joked. “I’m not taking anything from Thibs. Thibs is one of the better assistant coaches I ever played for. He helped me get better 10 years into the game. You don’t really see that a lot. Frank, he’s a little looser, a little more laid back. He’s going to joke with you a little bit more. That’s the biggest difference. At the end of the day, he’s going to get his work done and the players will respect him.”

To be fair, Thibodeau never really had much of a chance to show his personality with the media during his time in Boston, and he seems to be off to a good start with the Bulls, where he was credited with helping lure free agents to Chicago during the summer.

From the beginning, it was understood that Thibodeau would leave one day for a head-coaching job. He was too accomplished as an assistant and his defenses, especially with the Celtics, had become a signature component of his basketball identity. In his three years in Boston, Thibodeau had become the NBA’s version of a defensive coordinator and about as close to a brand-name as you can get for an assistant with no head coaching or playing experience.

It was also an interesting situation, in that Rivers brought Thibodeau aboard and gave him free reign to conduct the defense as he saw fit. It says something about Rivers’ trust in his own abilities that he would give an assistant coach that kind of responsibility.

For three years, the two made it work beautifully (along with Armond Hill and Kevin Eastman). Rivers was the unquestioned leader, while Thibodeau served as the mastermind of the feared Celtics defense. To call it a good working relationship is like saying Jagger and Richards wrote a couple of nice tunes together.

The Celtics went from 24th in opponents’ field goal percentage to second in Thibodeau’s first year and remained near the top of the defensive charts throughout his tenure. Of course, Kevin Garnett had a lot to do with that, as did the developments of Kendrick Perkins and Rajon Rondo, to say nothing of the renewed commitment to the defensive end from Pierce and Ray Allen. It all just blended together perfectly and everyone benefitted from the arrangement.

At long last, the Bulls came calling with not only an offer, but also a roster that seems ready to contend in the East. Finally, Thibodeau has his own chance to run a team.

Into the seat on the bench next to Rivers stepped Frank, and if you’re looking for him to be the new Thibs, you’re missing the larger point.

“They all bring what they bring to the game,” Pierce said. “Obviously, Thibs is a great coach in his own right, and so is Lawrence Frank. We’re not going to get into comparisons. That’s just like comparing Shaq to Rasheed [Wallace] a year ago. Lawrence’s credibility and respect around here fits great with the guys.” 

This is no small thing, because NBA teams in general, and the Celtics in particular, are typically hard to impress. “It’s hard to have veterans who have been around the block more than a few times give respect to somebody,” Pierce said. “It’s not like you can get anyone to fill that role.”

In 2004, Frank took over the Nets from Byron Scott after the latter had guided the woebegone franchise to back-to-back Finals appearances. He was 33-years-old at the time and there was talk of ego clashes and disagreements between Scott and his star player, Jason Kidd.

That’s not unusual in the NBA, but it soon became clear that even at a tender age, Frank was not going to back down from the task at hand. He went 25-15 during his first season and made it to the conference semifinals before losing in seven games to the eventual champion Pistons.

The Nets reached the second round two more times over the next three years, but as the team was broken up and scattered throughout the league, the inevitable rebuilding project began. It reached its nadir last season when Frank was let go after starting the season with 16 straight losses. It was more of a mercy killing than an execution and his reputation as a good basketball coach remains intact.

Frank took the rest of the year off, and his name emerged immediately as a potential replacement on Rivers’ staff. He said that he and Rivers had a mutual respect for each other from their time on opposite sidelines. “He always liked me because he always beat me,” Frank joked. “He tried to get me on the schedule two more times.”

But in the next breath, Frank offered a more sincere appreciation. “I was very grateful for the opportunity to join this franchise,” he said.

This season offers Frank a chance to regroup and recharge after grinding through the last few seasons with the Nets. “I never minded the media part,” Frank said of the demands of being a head coach. “It was the losing part that got me.” 

“This has been an ideal situation in that you look at the franchise, you look at the team, you look at the head coach and it’s a situation as an assistant, and I speak for all of us, we just do our jobs,” Frank continued. “You don’t have to worry about all of the other stuff that does go on in the league, especially when you have a group that’s so committed to winning a championship. It’s a very, very rare environment.”

Part of that environment is a testament to Thibodeau, whose defense remains in place, as well as the commitment to play it. Frank is here now and he will have his own chance to carve out a place in the Celtics hierarchy. It will be different, a little looser and less severe perhaps, but the Celtics should be in good hands.

“It’s all about our guys,” Frank said. “There’s a framework in place, both offensively and defensively. The challenge for all of us as a group, is sustaining the intensity on a daily basis.”