I just realized he's only got one year of experience in the league so "substantial offer" means Gilbert Arenas Provision Poison Pill offer a la Asik and Lin. However, the Knicks are screwed because of the taxpayer limitations on them.
The first-year salary in the offer sheet cannot be greater than the Non-Taxpayer Mid-Level exception
So basically the Hornets don't have to offer him a Poison Pill offer, they just have to offer something like 3/$12 and the Knicks can't match because they are limited to the Taxpayer MLE.
ETA: They may be able to go full MLE because of Jason Kidd retiring and JR Smith being likely to opt out would get them under the Tax Apron that changes the MLE. However I don't think the Knicks will renounce their rights to Smith and most teams keep retired player contracts floating around as trade chips, so they probably will be limited to the Taxpayer MLE for matching.
This post was edited on 6/25 at 8:14 am