newtonian mechanics - Angular momentum of a rotating sphere from a point outside the sphere

I have seen an expression for the angular momentum of a rotating sphere calculated from outside the sphere as $$L = I\omega + mvr,$$ where $v$ is the velocity of the center of mass, $m$ is the mass of the sphere, and $r$ is the distance of center of mass of the sphere from the point of calculation. My concern is if $v=0$, then $L = I \omega$, which is the angular momentum of the sphere when calculate through the center of mass. How can the angular momentum be the same when the point of calculation is changing?