Defensive raise with middle pair? yay or nay?
 

On the flop against a good, solid player.. solid player first to act and has made continuation/value/probe bets in the past and mixes them together.. sometimes he's had a hand, sometimes he folds when met with resistance..

Say you flop middle pair and villain bets out as he usually does. Half the pot or so on this occassion.. Would a defensive raise be a good idea? A call doesn't give much information, a raise can either win the pot or at least telly you he probably is beating you.. Should this move be implemented or should I just call and see what he does on 4th street?

Re: Defensive raise with middle pair? yay or nay?
 

Flopping the middle pair covers a lot of ground. Do you mean something like holding King Ten suited, and getting Queen Ten Seven rainbow on the flop?

Then I think you're saying your opponent is canny enough that he could have a pair of Aces, or Queen Jack, or Ace Seven, or he could have missed the flop; he might have made this bet with any of those hands or others. He could be raising because he's got you beat and will reraise, or because he wants to see how strong you are and will call, or because he has nothing and will fold to another raise.

While you obviously have to weigh the probabilities, this does not sound like a situation brimming with profit opportunities. Yes, you could pick up a nice pot with a bold raise. Yes, you might have the better hand and be favored to win at showdown. But I sense more danger than profit.

Calling would be my last choice. Sure you could get a King or a Ten on the turn, but there are only 5 of them left in the deck. The other 90% of the cards leave you in the same position you are now or worse. And, hey, you get to play again on the river.