Diamondbacks general manager Kevin Towers said the team is trying to decide whether Jason Kubel or Gerardo Parra is a better fit as their everyday left fielder in 2013. It's possible the "loser" of the two ends up being traded to short up another area. Kubel is the much better offensive player, but Parra is fantastic defensively and is under team control through 2015. "When you put a club together, it's more of a puzzle," Towers said. "What you do at short and third maybe changes what your need is in left. If you get more offense on the corner, then maybe there's more of a premium for the defender in left. If you don't get the offense and you get the defense in the infield, you have to have your power somewhere."