"It was one of those ideas," said Dunleavy, the Clippers' general manager and coach. "Hey, unless I ask him, I won't know."
Dunleavy said Thursday morning that Lucas, a respected former NBA player and coach, was at the team's offices in Playa Vista and would be joining the Clippers' coaching staff.
Lucas has a long-standing relationship with Dunleavy, and many of the current Clippers have worked out with Lucas at his Houston base.
"We talk all the time and we've always stayed in touch," Dunleavy said. "It was just one of those situations where I started thinking about guys who were available. Guys that were really good who have a lot of energy.
"So I called him. He said, 'I wouldn't do this for a lot of guys. Yeah, I will. For you, I'll come.' "
Dunleavy said that the agreement would be for one year.
Lucas' head coaching record in the NBA was 174-258 at stops in San Antonio, Philadelphia and Cleveland.