Creature w/ natural reach provokes AoO for attempting to start a grapple?

[ksbsnowowl]

In tomorrow's game, I'm going to have a troll under the affects of a fly potion, and he is going to position himself in front of the party druid, who is flying around as an Eagle (average maneuverability).

He will move up and attack, while the druid is at the extent of the troll's reach.  When the druid's turn comes, due to his average maneuverability, he will have the option to stall and fall out of the air (provoking an AoO), or move 5 feet toward the troll (provoking an AoO), turn 45 degrees, then fly past the troll.

The troll's plan for this resulting AoO is to start a grapple.  The troll does not have improved grapple, so he will provoke an AoO from the druid, however, at this point the druid doesn't threaten the troll...
Does the druid get the Attack of Opportunity in this case, even though he won't threaten the troll?

[Kethrian]

You can only make AoOs into squares you threaten.

[ksbsnowowl]

That's what I thought, but the grapple rules state:

Step 1

Attack of Opportunity. You provoke an attack of opportunity from the target you are trying to grapple.

It doesn't state you provoke an AoO if the foe threatens you.  It says it absolutely; you provoke an AoO.

Thus why I wanted to make sure.  Figured this could be one of those never-defined instances where you could attack, but not make a sneak attack, because you can't sneak attack when "striking the limbs of a creature whose vitals are beyond reach."

[Kethrian]

According to RAW, you can't take advantage of the provocation, because you don't threaten the foe, but I'd probably allow it in my campaigns because the limb would be within reach at the time.

[ksbsnowowl]

I'll probably say "no AoO," but just wanted to check.

[phaedrusxy]

RAW, no. You can't attack something you don't threaten. I agree that it makes sense that you could strike the limb, but that's not really how the rules work. You should be able to ready attacks to hit a creature with reach that's attacking you according to that logic, but that also doesn't actually work according to the rules.

[Ithamar]

Just agreeing that this is unfortunately the case and no AoO is allowed.  For what it is worth, this is backed up in the FAQ:

If an enemy makes an attack against me that would provoke an attack of opportunity (such as a disarm or grapple attempt), do I get the attack of opportunity if I can’t reach him? Would the Close-Quarters Fighting feat help at all?

Strictly speaking, if you don’t threaten an enemy, you can’t make attacks of opportunity against that enemy. Thus, if an ogre tried to sunder your elf’s longsword from 10 feet away, you wouldn’t get an attack of opportunity against the ogre (since an elf wielding a longsword doesn’t threaten an enemy 10 feet away). This is true even if the ogre is reaching out with his hand, such as when trying to grapple you.

Even the Close-Quarters Fighting feat doesn’t help, since that feat applies only when the attack of opportunity against a grappling foe normally would be denied by “a feat or special ability that would normally bypass the attack” and lists Improved Grapple and improved grab as examples.

The interesting thing I discovered just this morning though, is there is a RAW case where you can ready an action to hit a foe's body that has longer reach than you.  In the hydra entry it specifically states you can ready an action to sunder the head when the creature tries to bite you.