Timmeh, with regards to rookie list players:
A 1st year rookie not receiving a further rookie contract offer is considered a delisted free agent, and therefore is an unrestricted free agent. (Grimley fits in here).
A 1st year rookie who refuses a further rookie contract is NOT considered a delisted free agent and therefore is not an unrestricted free agent (and must nominate and go through the draft).
A 2nd year rookie not accepting a further rookie contract is considered a delisted free agent, and therefore is an unrestricted free agent. (ala Ballard).
With regards to Grimley.
Grimley was delisted by Hawthorn TWICE (2014 as a senior and 2015 as a rookie).
They have chosen to dump him in favour of Jack Fitzpatrick - a 22 games in 5 years, Melbourne delisting.
We have appointed David Hale as an assistant coach. Hale will have seen Grimley at close range over the past few seasons, let's hope we ask him for his honest opinion.
With regards to Mitch Brown, PK is spot on, he must nominate for the Draft.