[TomBrooks]

No one checkraises that board without an Ace or a Six. He's telling you that he wants the pot and is willing to take it now and if you want to draw to two outs you have to pay extra for it.

It's a kind of strange play though, because HU it's +EV to let you stay in and try to collect some more bets from you. If you don't have a pocket pair, your drawing to runner runner of one of your cards which is something like 475:1 I think. So hmmmm, could this be some kind of steal? Maybe with a lower pocket pair?

Edit after reading thread... I see some others are suspicious of this play also. I think it might have been worth calling this down to see what's up.

A cheaper way to find out if your not feeling as adventurous could be to 3-bet the flop. If he raises or even if he just calls, he ought to have the Ace. Otherwise, he would have to be a Moran, but from your read that doesn't seem to be the case. If he capped the flop, I'd fold. If he just called the flop three bet, I'd probably check through the turn if he checks and bet the river if he checks again.

Edit after reading Redd's post below... Actually, a thinking player would not cap with an Ace. But a thinking player would not have checkraised you either with an Ace. So, he's either real smart and tricky with a middle pocket pair and is not giving you credit for realizing that, or he not so smart and he got excited about his holding and played it too fast. The latter seems more likely.