I've noticed it generally gives a reasonable idea of the players "strongest" skills, box scores that is. It's not always 100% accurate, far from it but will give a fair idea. If the player gets off a bunch of assists and a few steals and not much else, his handling and passing are likely to be close if not his best attribues. Some of you could compile some results over a few seasons and see for yourself. I did this three seasons a couple of seasons back and it proved a decent indicator of their best skills. But and I reinterate, it will not determine or give a good indiction of the level of the skill. Example is I've had plenty of guys with 100% or close to it in FG% box score and had woeful shootings skills. Plus one guy with like 17 rebounds and only a rebounding of mediocre(though this was his joint highest skill). Anyways just my observations.
PS : I wouldn't bother with the guy and if your top, it would be better to invest them for next season like previous advice advocates. Good luck.