Do you think maybe he just hasn't found his passion? Does he have anything that really excites him? I think it's possible to be gifted but to mainly choose to use those gifts in one particular area--not necessarily an academic one-- due to interests and temperament.
Also, some kids are just late bloomers. How old is he?
He's in third grade. Things definitely excite him (Legos, minifigs, comic books, drawing out his own comic books, video games, playing chase with a nerf gun with the other boys). He's just not that interested in working hard to do what they want him to do at school in the interest of people-pleasing.
Even in K, I remember all of the homework sheets had coloring in them "just for fun" but it wasn't optional (?). He would refuse to finish the "fun" coloring, or he would do it super sloppy. I even gave up and started just coloring them with my left hand.
OTOH, my daughter sits with her K homework trying to make it look perfect because she wants to please the teacher.
