Dwyane Haskins says he ain't sure ... but did he just drop a massive clue??

Maybe ... 'cause the Ohio State QB -- who's out in NYC prepping for Saturday's Heisman Trophy ceremony -- told Adam Glyn ... "I'm pretty close to graduating."

Of course, most QBs facing the decision to stay in school or jump to the NFL put at least SOME weight on their degree when making the choice.

So, would Haskins finishing up his credits this year mean he's putting his name in the 2019 NFL Draft?

"I don't know yet," he says. "I gotta work it out with my parents and talk about it. I'm just enjoying the moment right now."

It wouldn't be the worst move for the redshirt sophomore ... 'cause most NFL mock draft experts have him pegged for the top half of the first round if he were to come out.