Gentry had a record of 39-43 in 2001-02, but was fired on March 3 after the team got off to a 19-39 start. In two-plus seasons at the helm of the Clippers, he was 89-133.
"Alvin has been in this league for a long time and he'll bring an invaluable amount of knowledge and experience to our staff," said Floyd. "I'm excited about working with him and using that knowledge to make our team better."
Prior to his stint with the Clippers, Gentry, 47, spent three seasons as coach of the Detroit Pistons, compiling a 73-72 record. He served as an assistant for San Antonio, the Clippers, and Miami, and was interim coach of the Heat in February 1995, when the team went 15-21 the remainder of that season.