I'm surprised he chose one that's basically impossible to cover, since he usually makes a point of covering his others (at least when he's playing).
But then, the other tattoos seem to have been about reclaiming his body and dealing with a traumatic experience. I remember him saying he got the big one on his back when the scars from his stabbing were still pink:
The one on his other arm is also stabbing related... it has a dagger through a basketball and says "my gift, my curse." He sometimes has a modified version on his shoes:

So in a way it's nice that he now has a "happy" tattoo... just celebrating his career and identity as the longtime heart of the last team he ever expected to join.