Kenley Jansen
Kenley Jansen will definitely not be resigning with Boston, he made many people in that organization angry after abandoning the team before their regular season was over. Jansen has publicly said he prioritizes winning over everything, but nobody would be surprised if he opts to pitch for the highest bidder rather than the best winning environment at this point in his long, accomplished career.
Jansen's 27 saves last season were one of the lowest marks of his career. His max velocity is way down. He just generally seems more lethargic these days too, and he often could only turn on his best stuff once he already let a base runner or two on.
One could easily make a case that if the Angels are serious about contending, then they should bring in an established closer and move Ben Joyce into a set-up role. This would help round out their bullpen too, putting less pressure on guys like Brock Burke, José Quijada, and Ryan Zeferjahn. That would not be the worst idea in the world. Just don't let that guy be Jansen.