I have no problem with Carrera as a 4th outfielder, and his salary reflects that role. The issue in the last few years is that he's had to play more than was ideal.
Our new found depth solved that, but meant that basically he or Pearce became superfluous. Carrera is out of options, while Pearce gives depth at 1B and DH (his better positions) and has a much higher guaranteed salary so if Pearce couldn't be traded then Carrera is the one who is unlucky.