Live 2/5 NLHE game. Effective stacks $675. Villain in question is a tight-aggressive pro in his mid-twenties who has a good understanding of hand-ranges.

Early position limper, mid position limper, villain limps on the button. I complete in the SB with 55, BB makes it $25 to go, everyone calls.

Flop is AJ5 $125 in pot.

Checked around.

Turn is Q

I lead for $75, BB folds, early position limper folds, mid position limper calls, villain on button makes it $325 to go. $250 to me, $575 left in my stack.

What's our play?

bet 75ish OTF you want value from aces and draws.... do not give 4 players a free card on this board... OTT i like the lead, but wow tough spot imo! so we can elim aa, qq, aq, aj and jj from his range,(or at least hugely discount) i dont think hes doing this with a naked ace though...the only hands i see him doing this with are heavy draws and the made straight given how you played the hand,he might put you on a naked ace, maybe a queen and someee air. he probably thinks he can push you off of and your hand is well disguised so id probably lean towards a call as the only hand that he can have here that has your crushed is k10 but even then you have outs and against everything else you beat

Lead flop. You'll get action from a lot of weak aces and FDs that won't bet if checked to.

AP, turn lead is good, but I make it a bit bigger. Now after the raise we are never folding, as there are no higher sets in a TAGs overlimping range. You lose to KT only, and he may even be raising or folding that PF. OTOH, you rep a weak hand and the limper's call reps weaker yet. There should be a lot of air, semi-bluffs, and weak made hands being turned in to bluffs in his range.

I shove it in here. An argument could be made for calling and shoving the river, in that on a blank river he could read you for a missed draw or some ish. There are few blank rivers, though, and if this guy is good he should realize how strong a flat here is. Plus, a bunch of cards kill your action and/or your hand. If you shove, OTOH, only his complete air should be able to fold, given the POs you'll be offering.

Since the BB was the pre-flop aggressor, my intention was to check, allow him to bet AT+, rope in multiple callers with Aces and flush-draws and check-raise them. I think a lead directly into the pre-flop aggressor looks WAY too strong on the flop and we may as well take advantage of our excellent relative position on the pre-flop aggressor and rope in some extra money. Flop line I have no problem with. Given that it didn't get bet, what do we do now? I think my lead on the turn is appropriate? I bet $75 into $125--I mean, we want action here from bad aces and flush draws, I am NOT trying to scare anyone off. Any bet sizing suggestions? But my main concern, is what do we do now?

Bear this in mind. Pro is the type who would bet AT+ on the flop in position vs 4 other players and likely any pair+flush draw like KJs, QJs, JTs, J9s, or something like a royal flush draw like KTs, QTs. Think about his check back range. Obv there are absolutely no higher sets in this guys range. After the MP calls, pot is $275 and it costs him $75 to see a river. If he has some **** like T9s or T8s, surely he would just call since he's getting close to the right immediate price, in position with a lot left to bet. 55, AJ, AQ, KT (maybe) are all in my range, does he really think this is a good spot to get aggro with a semi-bluff when calling is reasonable? He is a smart thinking player. Again, try to list the possible hands that he limps the button pre, calls the raise to $25 on the button after 3 others call, checks back the flop, and now goes nuts on the turn, knowing that he is well aware of my range. List those possible hands.

Always leading this flop. Only question is bet size.

hmm just through discussion you further broke down villians logical range and discounted the only hand that has an edge on you in terms of equity (kt) so first, in your original post, you asked whats the play, its really very simple now. try to get it in on the turn or the river? i think villians check back range from what you said mayyy be weaker draws...small sc. villain could easily but you on a weaker ace imo and his turn rr could very easily be an iso raise...