Baseball keeper question?

I am working on my keepers for my auction baseball league. I have good balance across my team so no other factors matter except what I am looking at. I have Matt Cain who is somewhat overpriced and Desmond Jennings who is beyond cheap. We have a minor league roster so I can stash Jennings until Manny or Damon gets hurt if I want. My other keepers at those positions are Jon Lester, Yovani Gallardo, Justin Verlander, Carlos Gonzalez and Shin Soo-Choo. Which one do I keep?