Ted Thompson tries to have as many options as possible.
What he doesn't like is a bad attitude player.
Bigby was given a chance by the Packers practice squad guy who was sent to NFL Europe to gain experience. For giving him a chance ahead of other players and paying him when he never got onto the field for years the Packers want some payback for that investment.
Bigby isn't getting younger and can't improve much more on his current skill set.
Smith and Peprah are adequate back ups. Burnett will need a year to learn.
Ted will let players fight it out in training camp to set the pecking order.