Linemen can go down field once the pass leaves the passer's hand not when it crosses the netural zone.

Well, not quite Andy..
Here's the NF reference: 7-5-12
it says, "...before a legal forward pass that crosses the NZ".
In most cases that will happen pretty quick.

[Edited by Theisey on Oct 4th, 2005 at 10:33 PM]

I agree with Andy.

7-5-12 Ineligible A players may not advance beyond the expanded neutral zone on a legal forward pass play before a legal forward pass which crosses the neutral zone is in <b>flight</b>. If B touches the pass in or behind the neutral zone, this restriction is terminated. An ineligible is not illegally downfield if, at the snap, he immediately contacts a B lineman and the contact does not continue beyond the expanded neutral zone.

[Edited by Warrenkicker on Oct 5th, 2005 at 10:15 AM]