McGruder spent the last three seasons with the Miami Heat. He averaged 7.6 points and 3.6 rebounds in 66 games (45 starts) last year.
"I am thankful for all of my family, friends and fans for supporting me through my journey!!" McGruder wrote on Twitter. "CLIPPER NATION LETS GET IT!!"
Miami waived McGruder on April 7 to get under the luxury tax. The Clippers grabbed him off waivers and were expected to re-sign him.
McGruder has averaged 6.7 points and 3.6 rebounds in 162 career games.