I see it two ways. If Julio can put a few good starts together and begins to look like the old Julio. If I'm looking to improve, Julio's stuff isn't as good a Gray, but he has produced, he has stayed healthy and he is signed longer. If I can get him somewhat cheaper (not a ton cheaper but a bit cheaper)...why would I not? Gray and Quintana have not set the world on fire either but will probably be asking for a lot.
I like the Astros also, because they have so much riches with bats, they could trade from an area of strength to make something happen. It wouldn't be that big of a deal for them to take a bit of a gamble on Julio.
I say we absolutely keep him, but then again....I think we have already seen the peak for him, and his real value lies in his contract, which is dwindling away as we speak. So, maybe now is the time if a decent offer is there.