That which must be done eventually must be done immediately. We all knew this was going to happen, no room on the roster for a 31 year old RB making $2.5M who doesn't play ST and last year fumbled at the rate of every other game.
IMO, the reason they waited this long was to avoid an injury settlement. MgGahee ended last season on IR. Broncos had to know he was fully healthy to ensure no injury settlement. They finally got him in to work yesterday, he checked out medically enough to practice, and can now wish him well.
Had McGahee participated in the voluntary workouts, he would have been cut then.