I'd re-raise to see if he has a set. He's certainly repping one, with his minbet/call pre-flop, and will probably push to a re-raise if he does. If he has a medium pair he'll *probably* fold, and if he has overcards he really, really should fold.

He could easily also have KJ or QJ, but I wouldn't want to end up on the river still uncertain what he has and possible losing a lot of money if I was either wrong or I get outdrawn.