Kinsler is not as good at 2B as Pedroia, and Craig is not the Red Sox' primary 1B, it is Mike Napoli who, surprisingly, has become a very good defensive 1B.
Pedroia had an 18.3 UZR last year, Kinsler checked in at 13.0 (still pretty good).
Napoli had a 5.0 UZR to Cabrera's -5.9.
Panda "holding up" has nothing to do with Porcello's current production. As it stands right now, Sandoval (3.5 UZR) is a pretty good 3B.