Al Horford had spent his entire nine-year NBA career with the Atlanta Hawks before signing a four-year, $113 million max contract with the Boston Celtics.
Horford participated in his first practice with the Celtics on Tuesday.
"It's definitely a weird feeling, but I feel good," Horford said. "It feels right to be here.
"I took a chance on coming here, because I believe in the type of guys we have here in the organization and the potential there is. So that's why I'm here, and I have a lot of respect for a lot of these players."
Horford is optimistic about the Celtics' younger core.
"It just really intrigued me, and when the free-agency process came around, at the beginning I would say I was very comfortable with Atlanta, but, as the time kept going on and I met with the Celtics, it just became real to me," Horford said.
"Looking at my career at this point, I'm going into my 10th year and want to be able to be a part of something special and win a championship. With the type of guys that we have here, we have that possibility, and that's something I wanted to be a part of."