This isn't an easy decision. If he is a tricky player I'd opt to check behind here, but normally I'd make a small value bet that could get him to call with a medium sized pocket pair. You can't go wrong with checking, but a small bet would be optimal since it's unlikely he has two pair or a set, but still possible. I'd put out a 15-20 dollar bet that he'll be priced into calling with a worse hand.