Last year, the Twins had 14 minor-league free agents they didn't re-sign (according to my records). They had 15 non-roster non-organizational spring training invites, most of whom weren't announced until later in the winter.
This year, the Twins have 17 currently not re-signed minor-league free agents (some still unsigned, some lost to others). The Twins have only signed four from other organizations. Obviously the door is still open for some of them to return - a name like Kyle Waldrop comes to mind - but it shouldn't come as any surprise if the Twins continue to add another dozen minor leaguers
I will be a little disappointed if the Twins add that many minor league free agents. You should lose about 15 minor league free agents a year near the top of the minor leagues just to make room for younger players moving up. If you have to replace all the minor league free agents you lost, with more minor league free agents, well then your young guys just aren't developing. That is pretty much what happened last year.
It seems like a lot of kids in the lower minors had pretty good years. I hope that means they are developing and ready to move up a level. What you hope happens is that there is a few players at AAA every year who move up to the majors. Ideally there should be around 10 AA players ready to move to AAA. The same all the way down the system. Of course it doesn't work that way in real life. There are mid-year promotions and injuries and often promising prospects stall out at higher levels. Still, if a minor league system is real healthy, it should be able to replace most of the minor league free agents and other dropouts from within the system.