There is no reason why both can't play in the majority of games. Davidson can play 3B or 1B which means he can spell Yolmer or Abreu & if he plays 3B Yolmer could spell Anderson or Moncada. Palka can play in the RF/LF (even though he sucks) one or two games and DH the rest. A lot Rick could play around with to make sure they are getting enough starts