"I feel like I'm suffocating and the person who helps me get through things have left me but I know your in a better place with no more worries no more hurt no more sadness or pain," Smart wrote. "Hate to let u go but I thank god for allowing me to have one of his angles (sic) to call my mom."
Camellia Smart was diagnosed with bone marrow cancer in April while Marcus was sidelined with a thumb injury, and urged him to return to the team despite her condition.
Throughout the postseason, Smart wrote messages for her on his shoes, such as "Mama's Boy," "I fight, you fight," and "F Cancer."
"Words can't express nor is there enough time in the world to tell u how much I love and miss u," he wrote. "So until we meet again I say R.I.P. To the strongest woman I know Camellia Smart my mom."
Smart's older brother, Todd, was also diagnosed with cancer and died in 2004 at age 33.