Opponent starts the hand with $45 and has done nothing remarkable, except that he's a bit passive. He's raised one or two hands preflop when it was limped to him, but he hasn't shown down anything yet. I'm guessing that when he raises preflop his range is something like AQ+, 99+.
I have KK on the button. One limper, shortstack makes it $4, I make it $15. Everyone folds, shortstack flat calls.
Flop: (pot=$31):
[8c][4s]. Opponent bets his remaining $30. I called.
Do you typically make this kind of call against an average shortstack player or is this spewing?