In the note, the 37-year-old wrote, "Dear Basketball, From the moment I started rolling my dad's tube sock and shooting imaginary game-winning shots … I fell in love with you."
The 17-time All-Star writes that it was a love so deep, he gave his all to the sport: "From my mind & body, to my spirit & soul."
The Los Angeles Lakers star made it clear that this will be his last season with the team.
"This season is all I have left to give," the 20-year veteran continued. "My heart can take the pounding, my mind can handle the grind, but my body knows it's time to say goodbye."
But he added that whatever he does next, he'll still be that kid throwing his dad's sock. "You gave a six-year-old boy his Laker dream, and I'll always love you for it."
Want stories like these delivered straight to your inbox? Sign up now for the Us Weekly newsletter!