I guess I'll go against the grain here. In a keeper format, I think I would take Corey Hart over Vlad. I'm not a huge Hart fan, and he did take a step backwards this season, but Vlad is really starting to get old, the power is seeping away and he doesn't run anymore. There's a legitimate chance that Hart could provide higher value in 4 of the usual 5 categories next year (all except BA) and he's about ten years younger. Draft Vlad in your first round after keepers if you want him still, but I'd go with youth here and keep Hart.
Vlad had his knee drained this offseason. Angels did pick up his option, but would not talk contract extension. This tells you something about his overall health. Of course, that could really motivate Vlad as well. Span could be next Crawford / Upton. Could have three 20/40 guys on your team. Obviously you trade one. Liriano. Post all star Liriano was as good as Santana.
How long is this keeper? 3yr? The longer the keeper, the more likely I would go with the risky play with more upside.