History says free agents signed by Kevin Colbert before June 1st are all but guaranteed to make the team. Knile Davis found out he was exception.
He joins Kevan Barlow as the two pre-June 1st signings (historically, when the compensation calculation ended) not to make the team. Justin Hunter could be the third but that was always seen as a special exception, the insurance policy to Martavis Bryant and a league that will hold out the carrot for as long as possible (and still are).