I'm on board with this only if Buxton is either regular CF or on the IL.
A regular outfield of Soler - Castro - Wallner or, slightly less so, Soler - Castro - Kepler with Gimpy Buxton at DH, while either Wallner or Kepler rides the pine, would be a defensive disaster for our flyball prone pitchers.
Soler OF 241 Innings (-3 OAA, -22.1 UZR/150)
Castro CF 261 Innings (-1 OAA, -19.1 UZR/150)
Wallner OF 487 Innings (-4 OAA, -0.4 UZR/150)
Kepler RF 972 Innings (4 OAA, 6.3 UZR/150)