Miller, 37, averaged 1.4 points, 1.9 rebounds and 1.1 assists last season in 20 games. He was scheduled to make $3.5 million in 2017, and his salary would have been guaranteed if he had not been waived before Wednesday.
He was part of the Heat's back-to-back NBA championship squads in 2011-12 and 2012-13.
Miller was the NBA's Sixth Man of the Year in 2005-06 while with the Grizzlies. He averaged 13.7 points that season and made 138 3-pointers.
In addition, Miller was named to the All-Rookie team in 2000-01 after being taken with the fifth overall pick by the Magic.
The Associated Press contributed to this report.