TP had a magical season and returned. He followed it up with a less impressive season and disappointing team effort. He then declared.
AWIII was on an awful team, knew he was going to be asked to do more than he was comfortable with so he bailed.
Morrow and Jacobsen knew what was coming with Palmer and Copeland and didn't want to be relegated to sharing minutes with each other and Jordy at the 5.
Everyone else who has left has essentially be non-factors that we all thought had "potential."
(Walt P was a very odd situation, don't see anyone like that on this team)
Frankly I don't see any of these applying to Palmer or Copeland. We didn't see major defections coming off the '14 run and I don't think we will after this season. Might we lose a Palmer or Tshimanga? Very possible. Maybe a seemingly random Allen or Akenten type defection? Very possible. I just don't see a scenario where we have a massive jumping of ship.