We know other teams covet him. It might be risky but we probably can afford to trade him (see: Dan Runzler and an improved MadBum). He might be more valuable now than ever . . .
. . . So if we could get a legitimate everyday player, would you pursue a deal? Who would you pursue? Ike Davis? Jose Reyes? Adam Jones? Please: don't say Jay Bruce or Joey Votto or Starlin Castro or Miguel Cabrera or Ryan Braun. Players that are the young face of a franchise; cost too much for our pocketbook; or are keys to a franchise on the cusp of the playoffs aren't going to trade away a key strength unless they have an equally strong backup for that position.
And of course there are teams, like the Yankees, who would love Jonathan but have nothing to trade us. We're talking realistic deals in which both teams get value. Two-for-one trades also considered. Maybe we get a lesser starting pitcher and a strong SS prospect in return.
One last thought: don't suggest trading Barry Z instead. No one is taking on that salary. Focus on Jonathan.