IMO, if he can reasonably play LF and OPS over .840, you have to keep Yonder Alonso and trade other (minor league) chips for a pitcher.
If he will not OPS over .840, he's not worth the trouble in LF and you should trade him for a frontline starter to improve the rotation.
If he cannot play a passable LF, the Reds need to trade him now. I'm not interested in keeping a pinch-hitter/2014 replacement in lieu of trying to win these next two years.
What do you think Yonder Alonso can reasonably OPS in the next two years?