BOSTON (CBS) — Marcus Smart will play the upcoming season with a heavy heart.

Smart’s mother, Camellia, passed away Sunday after a long battle with bone marrow cancer. The Celtics guard sent out an emotional tribute to his late mother Monday evening on his Twitter account.

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“You’ve always taught me hold my chin up and stay strong,” Smart wrote. “As I’m hearing you say it while typing this makes me cry deep inside and I feel like I’m suffocating and the person who helps me get through things [has] left me, but I know [you’re] in a better place with no more worries, no more hurt, no more sadness, or pain.”

“Hate to let u go but I thank god for allowing me to have one of his [angels] to call my mom,” he continued. “Words can’t express nor is there enough time in the world to tell u how much I love and miss u,” wrote Smart. “So until we meet again, I say R.I.P. to the strongest woman I know, Camellia Smart, my mom.”

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Smart often talked about his mother as a strong source of inspiration following his tough upbringing, and after being drafted sixth overall by the Celtics in 2014, he bought a home for her in Texas. He revealed her diagnosis in April as he came back from a thumb injury to join the Celtics for their postseason run, and often wrote “Mama’s Boy,” “I fight you fight.” and “F Cancer” on his sneakers during games.

Marcus Smart’s sneaker during the 2017-18 NBA playoffs with a message for his mother Camellia, who was battling bone marrow cancer at the time. (Photo by Mitchell Leff/Getty Images)

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While Smart and the Celtics worked out a four-year, $52 million extension over the offseason, he spent the majority of his time at home with his ailing mother.