200NL $1/$2 blinds

Me: $576
Villian: $556.33

Villian has built his stack calling down with lukewarm hands and holding up. Loose/passive and plays about 40% of his hands even when facing a raise. I've been stealing pots from him, as he will fold to a 2/3 pot bet without anything. On a previous hand I bet a top pair 8s with 86s after being the aggressor, got called and we checked it down from there. So I think he's onto my little game.

I'm in MP with
One limper and I raise to $8, villian calls on the button. blinds fold, limper folds.

Heads-up to the flop with $19.95 in the pot.

I bet $15, villian raises to $48.

What's your play?