Big fan, but I'd trade him at the deadline. It might not work out great this year, but I have no doubt they can fill the position next year. I'd just put Julien there and hope there aren't a lot of opportunities for him .....
Unless you want to put Lewis or Farmer (late innings for sure with the lead) there and put Farmer or Miranda at 3B (Lee isn't ready).
There is no guarantee that any of the options (Lewis, Lee, Martin, Julien, Severino......et. al.) will work, but, IMO, it is better to move on too soon, than too late. If they can get a top prospect for him, plus a flyer? I do that all day long and roll the dice that one of those guys is a good 2B next year.