Four years of service is the dividing line for the players being released

AP

Now that the offseason finally has begun and rosters have unlocked and players can be released, there’s an important distinction that becomes relevant for the first time since late October.

Any player who is released with less than four years of service must pass through waivers, with his current contract eligible to be claimed by any other team.  Any player who is released with four or more years of service becomes an unrestricted free agent immediately, free to sign with any other team at any time.

For example, Lions receiver Titus Young went through waivers, and he was claimed by the Rams.  Lions defensive end Kyle Vanden Bosch, in contrast, will become a free agent.  And he can now sign with the Rams, or anyone else he chooses to sign with.

As of the trade deadline, all players who are released must go through waivers, regardless of their years of experience.