Am I missing something here?

[ellipse_87]

Bump.

I actually could use some help with this one.

I suspect the answer is push, but I'm having trouble developing the rationale to get there.

Although diamonds represent a sizeable fraction of his holdings, we can't call and check-fold to a meaningful bet on a diamond turn. We'd be getting 3-1 at that point, (since he's down to 400 and likely autopushing), making it impossible to fold.

So since it's likely all going in anyway, maybe we should just push now.

Then again there's call then push the turn. There's a risk of folding a flush draw the 4/5 of the time a non-diamond will fall, since he's getting only 3-1 there; when he is all-in with a flush draw in that situation, we have a slight positive expectation when he calls as opposed to folding.

Then there's call, check-call his push if a diamond falls, inducing the semi-bluff by A9s/QTs/air.

So I've reasoned my way into this line: call, then push a non-diamond turn, check-call a diamond turn. I feel that the turn can't be checked on a non-diamond, because of the risk of giving a free card.

Any thoughts?

Edit: Well, the only reason to wait until the turn, it seems, is if he has a 9 and would push on a diamond turn if checked-to, but would fold the 9 to a flop push. Unlikely, given his raise compared to his stack size.

So nothing much good can be found in not pushing this flop, it seems.

Personally I'd get him all in.
IMO these hands come along seldom enough that you have to make them work for you. I like your bet out, often this will be taken as a steal and will get you some action.

The 2 diamonds on board would make me not want to keep it cheap in any way. If he slow played a big pair with a diamond in it he will call (more than likely even if not holding a diamond in a big pair) or he could well be on the draw or as you say could hold A9. Either way I want him in, you have him well covered so it's not a major disaster if he did hold the other J and bigger kicker. He's pretty much committed after his bet so if he didn't put you on a Jack he's in trouble.

It's always possible that he has pocket 9s - if so that's life.