He has been playing for the Idaho Stampede of the NBA's D-League, averaging 16.3 points and 9.5 rebounds in 23 games.
Ayres has appeared in 220 career regular-season games with Portland, Indiana and San Antonio during his five-year NBA career, averaging 3.0 points and 2.8 rebounds. He was on the Spurs' 2014 NBA championship team.
The 6-foot-10 forward was drafted with the 31st pick in 2009 by Sacramento and traded to Portland the same night.
The Clippers announced the deal Saturday. They are in the midst of a five-game road trip and next play at Toronto on Sunday.