Did I Get Pwned by Sklansky? - Strange 2-4 Hand

[Kevin J]

So there I was minding my own business in the BB when DS open limped from the sb and I checked with 9d,5d.

Flop comes AJ7 with one of my suit. DS checks, and I take a stab. He calls.

Turn is a 5. check-check.

River is a 9 and he checks. Ha! I'm thinking I just sucked out on the "Great One". I bet, he calls, and I lose to A7!?!?

Now when I say I question his play, I mean I question it to understand it....

I don't get the open limp, as I'm going to defend pretty liberally here. But I suppose it has merit, since I'm more likely to raise myself, and/or misjudge the strength of his hand.

I like (and understand), the flop check.

I also get the turn check. Not sure about the subsequent call though. He knows nothing of my play and can't know I'm not the type to call a check/raise with almost any pair or draw here.

I also don't get the river check/call. I suppose he'd hate to get 3-bet and to be honest, I'm not even sure I'd have him off. But I think he's leaving some money on the table against most players here. Then again, as strange as his play appears, he just may have made the maximum from me. Comments?