The Celtics have lost three of their last five games and center Kendrick Perkins blames a lack of focus.
Boston has lost back-to-back games to Atlanta and Indiana.
"I think our energy's been high, [but] these past few practices haven't been good, I don't think," Perkins said. "They haven't been our best practices. We've been turning over the ball, just being sloppy the last two practices.
"I thought as far as Doc and the coaching staff, they had the right game plan for practice. As a team, we haven't had the perfect execution for practice. We just gotta get back on the right track."
Perkins is confident that the Celtics will turn things around.
"We'll get it together," he said. "I just think each guy got to look at himself in the mirror and just play their roles, do their jobs, starting with me. I think I have to do a better job of setting picks, getting guys open, being better on the offensive end than what I am."