WALTHAM -- Boston Celtics general manager Danny Ainge thought Doc Rivers was going to be the next Gregg Popovich, Jerry Sloan or even Red Auerbach -- coaches who stayed with one team for decades.
Rivers got the nine-year itch.
"He felt like it was time for a change. He felt like we all needed a change," Ainge said on Tuesday night after the deal to allow Rivers out of his contract to coach the Los Angeles Clippers was final. "That was his rationalization, or justification, for going to the Clippers: that this was better for everybody."
After weeks of negotiations that at one time had Boston stars Kevin Garnett and Paul Pierce joining Rivers in Los Angeles, the Celtics announced on Tuesday that the NBA approved the deal to allow their coach to go to the Clippers in exchange for a first-round pick in 2015. Ainge said in a news conference that he had not begun looking for a new coach because he couldn't believe until late in the on-again, off-again process that Rivers was actually leaving.
"I haven't thought in anticipation of this," Ainge said. "It really, probably still hasn't hit me that this has happened. Probably because I thought it wasn't going to happen. I have not talked with one coaching candidate to this point."
One person who's not an option is Ainge himself.
"I'm not coaching," said the former Celtics point guard, who had a 136-90 record in three-plus seasons as the Phoenix Suns coach. "I've tried that. I tried that gig. I'm done with that.
Rivers had a 416-305 record in nine seasons in Boston, third in the history of the NBA's most-decorated franchise only to Auerbach and Tommy Heinsohn. But his tenure was really broken into two different eras: Before the New Big Three, and after it.
Rivers was 102-144 in his first three years in Boston, including a 2006-07 season in which the Celtics lost 18 straight games while plummeting to the bottom of the Eastern Conference standings in search of a star in the draft lottery. That summer, despite drawing the unfortunate fifth pick overall, Ainge acquired Garnett and Ray Allen to go with Pierce.
In their very first season together, they won 66 games and the NBA title -- the 17th in franchise history -- while giving birth to the notion that three stars could come together to make a superteam. The Celtics returned to the finals two years later, losing to the Los Angeles Lakers in seven games after center Kendrick Perkins was injured during the finals.
Rivers was 273-121 with the Big Three and 41-40 this season, when Allen left to help the Heat win the NBA title and Boston's stars seemed older and slower in a first-round playoff loss to the New York Knicks.
"Sometimes you've got to let your good people go to pursue what they need to pursue to make themselves happy," Celtics president Rich Gotham said. "While it's tough to see Doc go, I think we feel good about what he did here. We will be lucky to find as good a coach as Doc was."
Ainge said the prospect of rebuilding may have been one reason Rivers was looking to get out, but it should not have been a surprise to him.
"When we signed Doc to the highest-paid coaching contract in the NBA, we knew the ages of our players," Ainge said of the five-year, $35 million deal they gave him in 2011. "At that time, before it had hit him, he was all on board."
Now, Garnett is 37 with a no-trade clause and a contract that will pay him $23.5 million over the next two years; he has also discussed retiring. Pierce, the longest-tenured member of the team, is due to earn $15.3 million next season, when he will be 36; he could be bought out for $5 million, with the deadline at the end of the month.
Ainge said no decisions had been made to tear down the roster and rebuild.
"I love Paul and KG, and we haven't made that decision yet," he said. "KG is under contract and Paul we have an option on five days from now. Those are very big decisions for us. But I'm not certain."