Rothstein, 45, will be at a news conference today, the club said.
Lewis Schaffel, Heat managing partner, said the team has an oral agreement with Rothstein. "He's a teacher, one with patience," Schaffel said. "He's just the person we need to work with our young players."
Rothstein spent two years as an assistant coach with the Pistons. His name surfaced for coaching vacancies as the Pistons reached the NBA Finals this season.