To be honest, it's not much more than a 23-year-old wanting to get a job. Trevor can enjoy a fine career playing basketball professionally whether that's in the NBA or overseas. Had he come back, he would have been six years removed from high school.
For the 74th time, it's not about just "playing in the NBA."
If he gets to work with NBA coaches and they tell him things he needs to improve on to play professionally — in the NBA or elsewhere — it's worth it. Kam can make a fine living playing professional basketball in Turkey, Italy, Spain or wherever.
And he can still come back to Ohio State for another season before pursuing professional options next year.
Again, this isn't a big deal. There is minimal downside to getting a potential evaluation from NBA scouts.
It's not necessarily about "determining your Draft value" when it comes to these things. Having the opportunity to potentially workout for and receive feedback from NBA personnel can help you improve as a player. They tell you a ton of things you need to get better at to play professionally — in the NBA or elsewhere — and they can work on those things.
Actually think Michigan State is the favorite here, but Illinois is also a strong contender for obvious home school reasons. Ohio State fought like hell to get him to visit and it's probably his last visit before a decision so that could work heavily in their favor if all goes well.